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Guideline Summary
Guideline Title
Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period.
Bibliographic Source(s)
National Collaborating Centre for Women's and Children's Health. Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 38 p. (Clinical guideline; no. 129). 
Guideline Status

This is the current release of the guideline.

Scope

Disease/Condition(s)

Multiple pregnancy, including:

  • Twin pregnancy
  • Triplet pregnancy
Guideline Category
Counseling
Evaluation
Management
Screening
Clinical Specialty
Family Practice
Obstetrics and Gynecology
Intended Users
Advanced Practice Nurses
Health Care Providers
Nurses
Physician Assistants
Physicians
Guideline Objective(s)

To offer best practice advice on the care of women with twin and triplet pregnancies

Target Population

Women with twin and triplet pregnancies

Interventions and Practices Considered
  1. Determining gestational age and chorionicity
    • First trimester transabdominal ultrasound
    • Second opinion from senior ultrasonographer
    • Assigning and documenting nomenclature of babies
    • Transvaginal ultrasound, if indicated
  2. General care
    • Information and emotional support
    • Diet, lifestyle, nutritional supplements
    • Specialist care, including a multidisciplinary team
  3. Assessing fetal complications
    • Giving information and counselling on screening
    • Screening for Down's syndrome
    • Screening for structural abnormalities
    • Monitoring for feto-fetal transfusion syndrome
    • Monitoring for intrauterine growth restriction
  4. Assessing maternal complications, including hypertension
    • Measuring blood pressure and testing urine for proteinuria
    • Advising women to take aspirin
  5. Preterm birth
    • Predicting the risk of preterm birth
    • Preventing preterm birth
    • Advising women about untargeted corticosteroids
  6. Referral to a tertiary level fetal medicine centre
  7. Discussing with women the timing of birth
Major Outcomes Considered
  • Maternal morbidity and mortality during pregnancy and after birth
  • Perinatal and neonatal morbidity and mortality
  • Maternal satisfaction relating to the provision of antenatal care

Methodology

Methods Used to Collect/Select the Evidence
Searches of Electronic Databases
Description of Methods Used to Collect/Select the Evidence

Note from the National Guideline Clearinghouse (NGC): This guideline was developed by the National Collaborating Centre for Women's and Children's Health on behalf of the National Institute for Health and Clinical Excellence (NICE). See the "Availability of Companion Documents" field for the full version of this guidance.

The guideline development group (GDG) formulated review questions based on the scope (see Appendix D in the full guideline) and prepared a protocol for each review question (see Appendix E in the full guideline). These formed the starting point for systematic reviews of relevant evidence. Published evidence was identified by applying systematic search strategies (see Appendix F in the full guideline) to the following databases: Medline (1950 onwards), EMBASE (1980 onwards), Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 onwards) and three Cochrane databases (Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effects). Searches to identify economic studies were undertaken using the above databases, the National Health Service (NHS) Economic Evaluation Database (NHS EED) and the Health Technology Assessment (HTA) database. None of the searches was limited by date or language of publication (although publications in languages other than English were not reviewed). Generic and specially developed search filters were used to identify particular study designs, such as randomised controlled trials (RCTs). There was no systematic attempt to search grey literature (conference abstracts, theses or unpublished trials), nor was hand searching of journals not indexed on the databases undertaken.

Towards the end of the guideline development process, the searches were updated and re-executed to include evidence published and indexed in the databases by 1 November 2010.

Number of Source Documents

Not stated

Methods Used to Assess the Quality and Strength of the Evidence
Weighting According to a Rating Scheme (Scheme Given)
Rating Scheme for the Strength of the Evidence

Grading of Recommendations Assessment, Development and Evaluation (GRADE) Scheme

High: Further research is very unlikely to change the confidence in the estimate of effect

Moderate: Further research is likely to have an important impact on the confidence in the estimate of effect and may change the estimate

Low: Further research is very likely to have an important impact on the confidence in the estimate of effect and is likely to change the estimate

Very low: Any estimate of effect is very uncertain

Methods Used to Analyze the Evidence
Decision Analysis
Meta-Analysis
Review of Published Meta-Analyses
Systematic Review with Evidence Tables
Description of the Methods Used to Analyze the Evidence

Note from the National Guideline Clearinghouse (NGC): This guideline was developed by the National Collaborating Centre for Women's and Children's Health on behalf of the National Institute for Health and Clinical Excellence (NICE). See the "Availability of Companion Documents" field for the full version of this guidance.

Reviewing and Synthesising Evidence

Evidence relating to clinical effectiveness was reviewed and synthesised according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach (see http://www.gradeworkinggroup.org/index.htm External Web Site Policy). In the GRADE approach, the quality of the evidence identified for each outcome listed in the review protocol is assessed according to the factors listed below, and an overall quality rating (high, moderate, low or very low) is assigned by combining the ratings for the individual factors.

  • Study design (as an indicator of intrinsic bias; this determines the initial quality rating)
  • Limitations in the design or execution of the study (including concealment of allocation, blinding, loss to follow up; these can reduce the quality rating)
  • Inconsistency of effects across studies (this can reduce the quality rating)
  • Indirectness (the extent to which the available evidence fails to address the specific review question; this can reduce the quality rating)
  • Imprecision (this relates to statistical or clinical significance of reported effects; uncertainty in effects can reduce the quality rating)
  • Other considerations (including large magnitude of effect, evidence of a dose-response relationship, or confounding variables likely to have reduced the magnitude of an effect; these can increase the quality rating in observational studies, provided no downgrading for other features has occurred).

For each review question the highest available level of evidence was sought. Where appropriate, for example, if a systematic review, meta-analysis or RCT was identified to answer a question directly, studies of a weaker design were not considered. Where systematic reviews, meta-analyses and randomized controlled trials (RCTs) were not identified, other appropriate experimental or observational studies were sought. For diagnostic tests, test evaluation studies examining the performance of the test were used if the accuracy of the test was required, but where an evaluation of the effectiveness of the test in the clinical management of the condition was required, evidence from RCTs or cohort studies was optimal. For studies evaluating the accuracy of a diagnostic test, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratios for positive and negative test results (LR+ and LR–, respectively), were calculated or quoted where possible (see Table 3.2 in the full version of the original guideline document). If LR+ is between 5 and 10 it is classified as 'strong'; if LR+ is more than 10 it is classified as 'convincing'. If LR– is between 0.1 and 0.2 it is classified as 'strong'; if LR– is less than 0.1 it is classified as 'convincing'.

Some studies were excluded from the guideline reviews after obtaining copies of the corresponding publications because they did not meet inclusion criteria specified by the GDG (see Appendix G in the full version of the original guideline document). The characteristics of each included study were summarised in evidence tables for each review question (see Appendix H in the guideline appendices). Where possible, dichotomous outcomes were presented as relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs), and continuous outcomes were presented as mean differences (MDs) with 95% CIs or standard deviations (SDs). Absolute effects for dichotomous outcomes were calculated as the estimated relative effect (RR or OR) multiplied by an estimate of baseline risk (for a single study the baseline risk is the risk in the control group): absolute effects for continuous outcomes were estimated directly as the difference between outcomes in the different treatment groups.

The body of evidence identified for each review question (or part of a review question) was presented in the form of a GRADE findings table (evidence profile) summarising the quality of the evidence and the results (summary relative and absolute effect sizes and associated CIs). Where possible, the body of evidence corresponding to each outcome specified in the review protocol was subjected to quantitative meta-analysis. In such cases, summary effect sizes were presented as summary RRs, summary ORs or weighted mean differences (WMDs). Where summary RRs or summary ORs were estimated via meta-analysis the baseline risk was assumed to be the mean baseline risk in the studies included in the meta-analysis. By default, meta-analyses were conducted by fitting fixed effects models, but where unexplained heterogeneity was identified (I-squared statistic greater than 33%) random effects models were used. Where quantitative meta-analysis could not be undertaken (for example, because effect measures reported in the evidence were not accompanied by standard errors or data that would allow standard errors to be calculated), the range of effect sizes reported in the included studies was presented. Forest plots for all meta-analyses conducted for the guideline are presented in Appendix I of the guideline appendices. GRADE findings are presented in Appendix J of the guideline appendices and abbreviated versions (summary of findings without the individual components of the quality assessment) are presented in the full version of the original guideline document.

Various approaches may be used to assess imprecision in the GRADE framework. In this guideline, dichotomous outcomes in intervention studies were downgraded in terms of imprecision when the total number of events was less than 300 and continuous outcomes were downgraded when the total sample size was less than 400. These are default thresholds used in GRADE for intervention studies. For diagnostic test accuracy studies, evidence was downgraded in terms of imprecision when the width of the 95% CI for any of sensitivity, specificity, PPV or NPV was 40 percentage points or more, or if no CIs were reported. These thresholds or decision rules have been used in other NICE clinical guidelines.

Incorporating Health Economics

The aims of the health economic input to the guideline were to inform the GDG of potential economic issues relating to the management of twin and triplet pregnancies in the antenatal period, and to ensure that recommendations represented a cost-effective use of healthcare resources. Health economic evaluations aim to integrate data on benefits (ideally in terms of quality adjusted life years [QALYs]), harms and costs of different care options.

The GDG prioritised a number of review questions where it was thought that economic considerations would be particularly important in formulating recommendations. Systematic searches for published economic evidence were undertaken for these questions. For economic evaluations, no standard system of grading the quality of evidence exists and included papers were assessed using a quality assessment checklist based on good practice in economic evaluation. Reviews of the (very limited) relevant published health economic literature are presented alongside the clinical effectiveness reviews.

Health economic considerations were aided by original economic analysis undertaken as part of the development process. For this guideline the areas prioritised for economic analysis were cost effectiveness of:

  • Specialist multiple pregnancy care
  • Screening for feto-fetal transfusion syndrome (FFTS) (no cost effectiveness analysis was actually conducted for this review question because no evidence of clinical effectiveness was identified)
  • Screening to predict intrauterine growth restriction (IUGR) (no cost effectiveness analysis was actually conducted for this review question because no evidence of clinical effectiveness was identified)
  • Screening to predict the risks of spontaneous preterm birth and interventions for preventing spontaneous preterm birth (no cost effectiveness analysis was actually conducted for these review questions because no evidence of clinical effectiveness was identified)
  • Elective birth compared to expectant management

See the full version of the original guideline for information on the health economics of specialist versus usual care and elective birth versus expectant management.

Methods Used to Formulate the Recommendations
Expert Consensus (Nominal Group Technique)
Description of Methods Used to Formulate the Recommendations

Note from the National Guideline Clearinghouse (NGC): This guideline was developed by the National Collaborating Centre for Women's and Children's Health on behalf of the National Institute for Health and Clinical Excellence (NICE). See the "Availability of Companion Documents" field for the full version of this guidance.

For each review question recommendations for clinical care were derived using, and linked explicitly to, the evidence that supported them. In the first instance, informal consensus methods were used by the Guideline Development Group (GDG) to agree short clinical and, where appropriate, cost effectiveness evidence statements which were presented alongside the evidence profiles. Statements summarising the GDG's interpretation of the evidence and any extrapolation from the evidence used to form recommendations were also prepared to ensure transparency in the decision-making process. The criteria used in moving from evidence to recommendations are summarised as:

  • Relative value placed on the outcomes considered
  • Trade-off between clinical benefits and harms
  • Quality of the evidence
  • Other considerations (including equalities issues)

In areas where no substantial clinical research evidence was identified, the GDG considered other evidence-based guidelines and consensus statements or used its members' collective experience to identify good practice. The health economics justification in areas of the guideline where the use of National Health Service (NHS) resources (interventions or tests) was considered was based on GDG consensus in relation to the likely cost effectiveness implications of the recommendations. The GDG also identified areas where evidence to answer review questions was lacking and used this information to formulate recommendations for future research.

Towards the end of the guideline development process formal consensus methods were used to consider all the clinical care recommendations and research recommendations that had been drafted previously. The GDG identified ten 'key priorities for implementation' (key recommendations) and six high-priority research recommendations. The key priorities for implementation were those recommendations thought likely to have the biggest impact on pregnancy care and outcomes in the NHS as a whole; they were selected using a variant of the nominal group technique (see the NICE guidelines manual). The priority research recommendations were selected in a similar way.

Rating Scheme for the Strength of the Recommendations

Not applicable

Cost Analysis

Due to lack of clinical effectiveness evidence, health economic analyses were conducted only for cost effectiveness of specialist multiple pregnancy care compared to usual care and cost effectiveness of elective birth (at 37 weeks 0 days for multiple pregnancies) compared to expectant management. No relevant published economic evaluations were identified from literature searches. See the full version of the original guideline document (see the "Availability of Companion Documents" field) for details of the cost-effectiveness data and results.

Summary of Cost Effectiveness of Specialist Care Compared to Usual Care for Women with Twin or Triplet Pregnancies

Modelling demonstrated that, in a wide range of scenarios, specialist care for women with twin and triplet pregnancies saves costs compared to usual care (routine antenatal care). The savings were driven primarily by reduced costs due to a lower risk of adverse neonatal events requiring hospitalisation in the specialist care group. Probabilistic sensitivity analysis showed that the probability of specialist care being cost effective was greater than 99% for monochorionic diamniotic twin pregnancies, dichorionic twin pregnancies and triplet pregnancies when compared with usual care.

A major strength of this analysis is that the model considered the potential improvement in health outcomes for both the woman and the babies. To the guideline development group's (GDG's) knowledge this is the first economic analysis of its kind. However, the clinical effectiveness data were taken from medium-quality studies which were mainly undertaken in the USA. Extrapolating from these studies to an NHS setting is clearly an important limitation of this model. Data were not reported separately by chorionicity, and the GDG therefore assumed reported outcomes would apply equally to monochorionic and dichorionic twin pregnancies, which may not be the case. This may overestimate the impact of specialist care for dichorionic twin pregnancies and probably underestimates the impact for monochorionic twin pregnancies which have a much higher risk of adverse outcomes.

Summary of Cost Effectiveness of Elective Birth Compared to Expectant Management for Multiple Pregnancies

The data used in this model suggest that prolonging multiple pregnancies beyond 37 weeks 0 days increases the QALY loss (see Table 11.13 in the full version of the original guideline document). If 37 weeks 0 days, as per the elective birth strategy, is the optimal timing in terms of clinical outcomes, then expectant management can only be preferred if it produces significant savings relative to elective birth. If that were the case, the better outcomes of elective birth would not be worth the opportunity cost, as the savings could produce greater benefit by being used in an alternative way.

This model did not explicitly cost the different strategies. Instead, in Table 11.13 a threshold analysis is presented to show the incremental saving that would be necessary, using the advisory willingness to pay threshold of £20,000 per QALY suggested in the NICE guidelines manual, to make each additional week of expectant management cost effective relative to elective birth 1 week earlier.

The model using the available clinical evidence suggests that elective birth at 37 weeks 0 days for multiple pregnancies, and dichorionic twin pregnancies in particular, is cost effective relative to a strategy of expectant management beyond this gestational age.

Method of Guideline Validation
External Peer Review
Internal Peer Review
Description of Method of Guideline Validation

The guideline was validated through two consultations.

  1. The first draft of the guideline (the full guideline, National Institute for Health and Clinical Excellence [NICE] guideline, and Quick Reference Guide) were consulted with Stakeholders and comments were considered by the Guideline Development Group (GDG)
  2. The final consultation draft of the full guideline, the NICE guideline and the Information for the Public were submitted to stakeholders for final comments.

The final draft was submitted to the Guideline Review Panel for review prior to publication.

Recommendations

Major Recommendations

Note from the National Guideline Clearinghouse (NGC): This guideline was developed by the National Collaborating Centre for Women's and Children's Health on behalf of the National Institute for Health and Clinical Excellence (NICE). See the "Availability of Companion Documents" field for the full version of this guidance.

The following guidance is based on the best available evidence. The full guideline (www.nice.org.uk/guidance/CG129 External Web Site Policy) gives details of the methods and the evidence used to develop the guidance.

This guideline should be read in conjunction with 'Antenatal care' NICE clinical guideline 62 (see the NICE guideline Antenatal care). This guideline specifies the care that women with twin and triplet pregnancies should receive that is additional or different from routine antenatal care for women with singleton pregnancies. Table 5.8 in the full version of the original guideline document shows a comparison of the schedule of appointments for women with singleton pregnancies and women with multiple pregnancies.

Note that for many women the twin or triplet pregnancy will be detected only after their routine booking appointment. Women should then be offered the specialist antenatal appointments as outlined below.

Determining Gestational Age and Chorionicity

See Appendix E in the full version of the original guideline document for definitions of key terms used in this guideline (including chorionicity and amnionicity).

Gestational Age

Offer women with twin and triplet pregnancies a first trimester ultrasound scan when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) to estimate gestational age, determine chorionicity and screen for Down's syndrome (ideally, these should all be performed at the same scan; see the first two entries under 'Chorionicity' below).*

*'Antenatal care' (see the NICE guideline Antenatal care) recommends determination of gestational age from 10 weeks 0 days. However, the aim in this recommendation is to keep to a minimum the number of scan appointments that women need to attend within a short time, especially if it is already known that a woman has a twin or triplet pregnancy.

Use the largest baby to estimate gestational age in twin and triplet pregnancies to avoid the risk of estimating it from a baby with early growth pathology.

Chorionicity

Determine chorionicity at the time of detecting twin and triplet pregnancies by ultrasound using the number of placental masses, the lambda or T-sign and membrane thickness.

Assign nomenclature to babies (for example, upper and lower, or left and right) in twin and triplet pregnancies and document this clearly in the woman's notes to ensure consistency throughout pregnancy.

If a woman with a twin or triplet pregnancy presents after 14 weeks 0 days, determine chorionicity at the earliest opportunity by ultrasound using all of the following:

  • The number of placental masses
  • The lambda or T-sign
  • Membrane thickness
  • Discordant fetal sex

If it is not possible to determine chorionicity by ultrasound at the time of detecting the twin or triplet pregnancy, seek a second opinion from a senior ultrasonographer or offer the woman referral to a healthcare professional who is competent in determining chorionicity by ultrasound scan as soon as possible.

If it is difficult to determine chorionicity, even after referral (for example, because the woman has booked late in pregnancy), manage the pregnancy as monochorionic until proved otherwise.

Provide regular training so that ultrasonographers can identify the lambda or T-sign accurately and confidently. Less experienced ultrasonographers should have support from senior colleagues.

Training should cover ultrasound scan measurements needed for women who book after 14 weeks 0 days and should emphasise that the risks associated with twin and triplet pregnancies are determined by chorionicity and not zygosity.

Conduct regular clinical audits to evaluate the accuracy of determining chorionicity.

If transabdominal ultrasound scan views are poor because of a retroverted uterus or a high body mass index (BMI), use a transvaginal ultrasound scan to determine chorionicity.

Do not use three-dimensional ultrasound scans to determine chorionicity.

Networks should agree care pathways for managing all twin and triplet pregnancies to ensure that each woman has a care plan in place that is appropriate for the chorionicity of her pregnancy.

General Care

Information and Emotional Support

Explain sensitively the aims and possible outcomes of all screening and diagnostic tests to women with twin and triplet pregnancies to minimise their anxiety.

Diet, Lifestyle and Nutritional Supplements

Give women with twin and triplet pregnancies the same advice about diet, lifestyle and nutritional supplements as in routine antenatal care*.

*See the NICE guideline Antenatal care.

Be aware of the higher incidence of anaemia in women with twin and triplet pregnancies compared with women with singleton pregnancies.

Perform a full blood count at 20–24 weeks to identify women with twin and triplet pregnancies who need early supplementation with iron or folic acid, and repeat at 28 weeks as in routine antenatal care.*

*This is in addition to the test for anaemia at the routine booking appointment; see the NICE guideline Antenatal care.

Specialist Care

Clinical care for women with twin and triplet pregnancies should be provided by a nominated multidisciplinary team consisting of:

  • A core team of named specialist obstetricians, specialist midwives and ultrasonographers, all of whom have experience and knowledge of managing twin and triplet pregnancies
  • An enhanced team for referrals, which should include:
    • A perinatal mental health professional
    • A women's health physiotherapist
    • An infant feeding specialist
    • A dietitian

Members of the enhanced team should have experience and knowledge relevant to twin and triplet pregnancies.

Referrals to the enhanced team should not be made routinely for women with twin and triplet pregnancies but should be based on each woman's needs.

Coordinate clinical care for women with twin and triplet pregnancies to:

  • Minimise the number of hospital visits
  • Provide care as close to the woman's home as possible
  • Provide continuity of care within and between hospitals and the community

The core team should offer information and emotional support specific to twin and triplet pregnancies at their first contact with the woman and provide ongoing opportunities for further discussion and advice including:

  • Antenatal and postnatal mental health and wellbeing
  • Antenatal nutrition (see 'Diet, Lifestyle and Nutritional Supplements' above)
  • The risks, symptoms and signs of preterm labour and the potential need for corticosteroids for fetal lung maturation
  • Likely timing and possible modes of delivery*
  • Breastfeeding
  • Parenting

*Specific recommendations about mode of delivery are outside the scope of this guideline.

Offer women with uncomplicated monochorionic diamniotic twin pregnancies at least nine antenatal appointments with a healthcare professional from the core team. At least two of these appointments should be with the specialist obstetrician.

  • Combine appointments with scans when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) and then at estimated gestations of 16, 18, 20, 22, 24, 28, 32 and 34 weeks (see 'Timing of Birth' below).*

Offer women with uncomplicated dichorionic twin pregnancies at least eight antenatal appointments with a healthcare professional from the core team. At least two of these appointments should be with the specialist obstetrician.

  • Combine appointments with scans when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) and then at estimated gestations of 20, 24, 28, 32 and 36 weeks (see 'Timing of Birth' below).*
  • Offer additional appointments without scans at 16 and 34 weeks.

Offer women with uncomplicated monochorionic triamniotic and dichorionic triamniotic triplet pregnancies at least 11 antenatal appointments with a healthcare professional from the core team. At least two of these appointments should be with the specialist obstetrician.

  • Combine appointments with scans when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) and then at estimated gestations of 16, 18, 20, 22, 24, 26, 28, 30, 32 and 34 weeks (see 'Timing of Birth' below).*

Offer women with uncomplicated trichorionic triamniotic triplet pregnancies at least seven antenatal appointments with a healthcare professional from the core team. At least two of these appointments should be with the specialist obstetrician.

  • Combine appointments with scans when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) and then at estimated gestations of 20, 24, 28, 32 and 34 weeks (see 'Timing of Birth' below).*
  • Offer an additional appointment without a scan at 16 weeks.

Women with twin and triplet pregnancies involving a shared amnion should be offered individualised care from a consultant in a tertiary level fetal medicine centre (see 'Indications for Referral to a Tertiary Level Fetal Medicine Centre' below).

*See Appendix D in the original guideline document for recommendations for 'Schedule of specialist antenatal appointments' in table form.

Fetal Complications

Information About Screening

A healthcare professional with experience of caring for women with twin and triplet pregnancies should offer information and counselling to women before and after every screening test.

Inform women with twin and triplet pregnancies about the complexity of decisions they may need to make depending on the outcomes of screening, including different options according to the chorionicity of the pregnancy.

Screening for Down's Syndrome

Before screening for Down's syndrome offer women with twin and triplet pregnancies information about:

  • The greater likelihood of Down's syndrome in twin and triplet pregnancies
  • The different options for screening*
  • The false positive rate of screening tests, which is higher in twin and triplet pregnancies
  • The likelihood of being offered invasive testing, which is higher in twin and triplet pregnancies
  • The greater likelihood of complications of invasive testing
  • The physical risks and psychological implications in the short and long term relating to selective fetal reduction

*See the NICE guideline Antenatal care.

Healthcare professionals who screen for Down's syndrome in twin pregnancies should:

  • Map the fetal positions
  • Use the combined screening test (nuchal translucency, beta-human chorionic gonadotrophin, pregnancy-associated plasma protein-A) for Down's syndrome when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days; see 'Gestational Age' above)
  • Calculate the risk of Down's syndrome per pregnancy in monochorionic twin pregnancies
  • Calculate the risk of Down's syndrome for each baby in dichorionic twin pregnancies.

Healthcare professionals who screen for Down's syndrome in triplet pregnancies should:

  • Map the fetal positions
  • Use nuchal translucency and maternal age to screen for Down's syndrome when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days; see 'Gestational Age' above)
  • Calculate the risk of Down's syndrome per pregnancy in monochorionic triplet pregnancies
  • Calculate the risk of Down's syndrome for each baby in dichorionic and trichorionic triplet pregnancies.

Where first trimester screening for Down's syndrome cannot be offered to a woman with a twin pregnancy (for example, if the woman books too late in pregnancy) consider second trimester serum screening and explain to the woman the potential problems of such screening. These include the increased likelihood of pregnancy loss associated with double invasive testing because the risk of Down's syndrome cannot be calculated separately for each baby.

Do not use second trimester serum screening for Down's syndrome in triplet pregnancies.

Offer women with twin and triplet pregnancies who have a high risk of Down's syndrome (use a threshold of 1:150 as defined by the National Health Service [NHS] Fetal Anomaly Screening Programme [FASP]*) referral to a fetal medicine specialist in a tertiary level fetal medicine centre.

*See http://fetalanomaly.screening.nhs.uk/standardsandpolicies External Web Site Policy.

Screening for Structural Abnormalities

Offer screening for structural abnormalities (such as cardiac abnormalities) in twin and triplet pregnancies as in routine antenatal care.*

*See the NICE guideline Antenatal care. Also available from www.nice.org.uk/guidance/CG62 External Web Site Policy and also http://fetalanomaly.screening.nhs.uk/standardsandpolicies External Web Site Policy.

Consider scheduling ultrasound scans in twin and triplet pregnancies at a slightly later gestational age than in singleton pregnancies and be aware that the scans will take longer to perform.

Allow 45 minutes for the anomaly scan in twin and triplet pregnancies (as recommended by FASP)*.

*See http://fetalanomaly.screening.nhs.uk/standardsandpolicies External Web Site Policy.

Allow 30 minutes for growth scans in twin and triplet pregnancies.

Monitoring for Feto-fetal Transfusion Syndrome

Do not monitor for feto-fetal transfusion syndrome in the first trimester.

Start diagnostic monitoring with ultrasound for feto-fetal transfusion syndrome (including to identify membrane folding) from 16 weeks. Repeat monitoring fortnightly until 24 weeks.

Carry out weekly monitoring of twin and triplet pregnancies with membrane folding or other possible early signs of feto-fetal transfusion syndrome (specifically, pregnancies with intertwin membrane infolding and amniotic fluid discordance) to allow time to intervene if needed.

Monitoring for Intrauterine Growth Restriction

Do not use abdominal palpation or symphysis–fundal height measurements to predict intrauterine growth restriction in twin or triplet pregnancies.

Estimate fetal weight discordance using two or more biometric parameters at each ultrasound scan from 20 weeks. Aim to undertake scans at intervals of less than 28 days. Consider a 25% or greater difference in size between twins or triplets as a clinically important indicator of intrauterine growth restriction and offer referral to a tertiary level fetal medicine centre.

Do not use umbilical artery Doppler ultrasound to monitor for intrauterine growth restriction or birthweight differences in twin or triplet pregnancies.

Maternal Complications

Hypertension

Measure blood pressure and test urine for proteinuria to screen for hypertensive disorders at each antenatal appointment in twin and triplet pregnancies as in routine antenatal care.*

*See the NICE guideline Antenatal care.

Advise women with twin and triplet pregnancies that they should take 75 mg of aspirin* daily from 12 weeks until the birth of the babies if they have one or more of the following risk factors for hypertension:

  • First pregnancy
  • Age 40 years or older
  • Pregnancy interval of more than 10 years
  • Body mass index (BMI) of 35 kg/m2 or more at first visit
  • Family history of pre-eclampsia

*At the time of publication (September 2011) this drug did not have UK marketing authorisation for this indication. Informed consent should be obtained and documented. (This recommendation is adapted from recommendation 1.1.2.2 in 'Hypertension in pregnancy'; see the NICE guideline Hypertension in pregnancy.)

Preterm Birth

Predicting the Risk of Preterm Birth

Be aware that women with twin pregnancies have a higher risk of spontaneous preterm birth if they have had a spontaneous preterm birth in a previous singleton pregnancy.

Do not use fetal fibronectin testing alone to predict the risk of spontaneous preterm birth in twin or triplet pregnancies.

Do not use home uterine activity monitoring to predict the risk of spontaneous preterm birth in twin or triplet pregnancies.

Do not use cervical length (with or without fetal fibronectin) routinely to predict the risk of spontaneous preterm birth in twin or triplet pregnancies.

Preventing Preterm Birth

Do not use the following interventions (alone or in combination) routinely to prevent spontaneous preterm birth in twin or triplet pregnancies:

  1. Bed rest at home or in hospital
  2. Intramuscular or vaginal progesterone
  3. Cervical cerclage
  4. Oral tocolytics

Untargeted Corticosteroids

Inform women with twin and triplet pregnancies of their increased risk of preterm birth and about the benefits of targeted corticosteroids.

Do not use single or multiple untargeted (routine) courses of corticosteroids in twin or triplet pregnancies. Inform women that there is no benefit in using untargeted administration of corticosteroids.

Indications for Referral to a Tertiary Level Fetal Medicine Centre

Seek a consultant opinion from a tertiary level fetal medicine centre for:

  • Monochorionic monoamniotic twin pregnancies
  • Monochorionic monoamniotic triplet pregnancies
  • Monochorionic diamniotic triplet pregnancies
  • Dichorionic diamniotic triplet pregnancies
  • Pregnancies complicated by any of the following:
    • Discordant fetal growth
    • Fetal anomaly
    • Discordant fetal death
    • Feto-fetal transfusion syndrome

Timing of Birth

Discuss with women with twin and triplet pregnancies the timing of birth and possible modes of delivery* early in the third trimester.

Inform women with twin pregnancies that about 60% of twin pregnancies result in spontaneous birth before 37 weeks 0 days.

Inform women with triplet pregnancies that about 75% of triplet pregnancies result in spontaneous birth before 35 weeks 0 days.

Inform women with twin and triplet pregnancies that spontaneous preterm birth and elective preterm birth are associated with an increased risk of admission to a special care baby unit.

Inform women with uncomplicated monochorionic twin pregnancies that elective birth from 36 weeks 0 days does not appear to be associated with an increased risk of serious adverse outcomes, and that continuing uncomplicated twin pregnancies beyond 38 weeks 0 days increases the risk of fetal death.

Inform women with uncomplicated dichorionic twin pregnancies that elective birth from 37 weeks 0 days does not appear to be associated with an increased risk of serious adverse outcomes, and that continuing uncomplicated twin pregnancies beyond 38 weeks 0 days increases the risk of fetal death.

Inform women with triplet pregnancies that continuing uncomplicated triplet pregnancies beyond 36 weeks 0 days increases the risk of fetal death.

Offer women with uncomplicated:

  • Monochorionic twin pregnancies elective birth* from 36 weeks 0 days, after a course of antenatal corticosteroids has been offered
  • Dichorionic twin pregnancies elective birth* from 37 weeks 0 days
  • Triplet pregnancies elective birth* from 35 weeks 0 days, after a course of antenatal corticosteroids has been offered.

For women who decline elective birth, offer weekly appointments with the specialist obstetrician. At each appointment offer an ultrasound scan, and perform weekly biophysical profile assessments and fortnightly fetal growth scans.

*Specific recommendations about mode of delivery are outside the scope of this guideline.

Clinical Algorithm(s)

The following algorithms are available in the Quick Reference Guide (see the "Availability of Companion Documents" field):

  • Determining gestational age and chorionicity
  • Planning care according to chorionicity
  • Screening for Down's syndrome
  • Timing of birth

Evidence Supporting the Recommendations

Type of Evidence Supporting the Recommendations

The type of evidence supporting the recommendations is not specifically stated.

Benefits/Harms of Implementing the Guideline Recommendations

Potential Benefits

Appropriate patient-centred care for women with twin or triplet pregnancies

Potential Harms

False positive test results

Qualifying Statements

Qualifying Statements
  • This guidance represents the view of the National Institute for Health and Clinical Excellence (NICE), which was arrived at after careful consideration of the evidence available. Healthcare professionals are expected to take it fully into account when exercising their clinical judgement. However, the guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer, and informed by the summary of product characteristics of any drugs they are considering.
  • Implementation of this guidance is the responsibility of local commissioners and/or providers. Commissioners and providers are reminded that it is their responsibility to implement the guidance, in their local context, in light of their duties to avoid unlawful discrimination and to have regard to promoting equality of opportunity. Nothing in this guidance should be interpreted in a way that would be inconsistent with compliance with those duties.

Implementation of the Guideline

Description of Implementation Strategy

The National Institute for Health and Clinical Excellence (NICE) has developed tools to help organisations implement this guidance. These are available on the NICE Web site (http://guidance.nice.org.uk/CG129 External Web Site Policy; see also the "Availability of Companion Documents" field).

Key Priorities for Implementation

The following recommendations have been identified as priorities for implementation.

Determining Gestational Age and Chorionicity

  • Offer women with twin and triplet pregnancies a first trimester ultrasound scan when crown–rump length measures from 45 mm to 84 mm (at approximately 11 weeks 0 days to 13 weeks 6 days) to estimate gestational age, determine chorionicity and screen for Down's syndrome (ideally, these should all be performed at the same scan)*.
  • Determine chorionicity at the time of detecting twin and triplet pregnancies by ultrasound using the number of placental masses, the lambda or T-sign and membrane thickness.
  • Assign nomenclature to babies (for example, upper and lower, or left and right) in twin and triplet pregnancies and document this clearly in the woman's notes to ensure consistency throughout pregnancy.
  • Networks should agree care pathways for managing all twin and triplet pregnancies to ensure that each woman has a care plan in place that is appropriate for the chorionicity of her pregnancy.

Specialist Care

  • Clinical care for women with twin and triplet pregnancies should be provided by a nominated multidisciplinary team consisting of:
    • A core team of named specialist obstetricians, specialist midwives and ultrasonographers, all of whom have experience and knowledge of managing twin and triplet pregnancies
    • An enhanced team for referrals, which should include:
      • A perinatal mental health professional
      • A women's health physiotherapist
      • An infant feeding specialist
      • A dietitian

Members of the enhanced team should have experience and knowledge relevant to twin and triplet pregnancies.

  • Coordinate clinical care for women with twin and triplet pregnancies to:
    • Minimise the number of hospital visits
    • Provide care as close to the woman's home as possible
    • Provide continuity of care within and between hospitals and the community
  • The core team should offer information and emotional support specific to twin and triplet pregnancies at their first contact with the woman and provide ongoing opportunities for further discussion and advice including:
    • Antenatal and postnatal mental health and wellbeing
    • Antenatal nutrition
    • The risks, symptoms and signs of preterm labour and the potential need for corticosteroids for fetal lung maturation
    • Likely timing and possible modes of delivery**
    • Breastfeeding
    • Parenting

Monitoring for Intrauterine Growth Restriction

  • Estimate fetal weight discordance using two or more biometric parameters at each ultrasound scan from 20 weeks. Aim to undertake scans at intervals of less than 28 days. Consider a 25% or greater difference in size between twins or triplets as a clinically important indicator of intrauterine growth restriction and offer referral to a tertiary level fetal medicine centre.

Indications for Referral to a Tertiary Level Fetal Medicine Centre

  • Seek a consultant opinion from a tertiary level fetal medicine centre for:
    • Monochorionic monoamniotic twin pregnancies
    • Monochorionic monoamniotic triplet pregnancies
    • Monochorionic diamniotic triplet pregnancies
    • Dichorionic diamniotic triplet pregnancies
    • Pregnancies complicated by any of the following:
      • Discordant fetal growth
      • Fetal anomaly
      • Discordant fetal death
      • Feto-fetal transfusion syndrome

Timing of Birth

  • Offer women with uncomplicated:
    • Monochorionic twin pregnancies elective birth** from 36 weeks 0 days, after a course of antenatal corticosteroids has been offered
    • Dichorionic twin pregnancies elective birth** from 37 weeks 0 days
    • Triplet pregnancies elective birth** from 35 weeks 0 days, after a course of antenatal corticosteroids has been offered.

*'Antenatal care' (see the NICE guideline Antenatal care) recommends determination of gestational age from 10 weeks 0 days. However, the aim in this recommendation is to keep to a minimum the number of scan appointments that women need to attend within a short time, especially if it is already known that a woman has a twin or triplet pregnancy.

** Specific recommendations about mode of delivery are outside the scope of this guideline.

Implementation Tools
Audit Criteria/Indicators
Clinical Algorithm
Foreign Language Translations
Patient Resources
Quick Reference Guides/Physician Guides
Resources
Slide Presentation
For information about availability, see the Availability of Companion Documents and Patient Resources fields below.

Institute of Medicine (IOM) National Healthcare Quality Report Categories

IOM Care Need
Staying Healthy
IOM Domain
Effectiveness
Patient-centeredness
Safety

Identifying Information and Availability

Bibliographic Source(s)
National Collaborating Centre for Women's and Children's Health. Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 38 p. (Clinical guideline; no. 129). 
Adaptation

Not applicable: The guideline was not adapted from another source.

Date Released
2011 Sep
Guideline Developer(s)
National Collaborating Centre for Women's and Children's Health - National Government Agency [Non-U.S.]
Source(s) of Funding

National Institute for Health and Clinical Excellence

Guideline Committee

Guideline Development Group

Composition of Group That Authored the Guideline

Guideline Development Group (GDG) Members: Jane Anderson, Lead Sonographer, Obstetric and Gynaecology Ultrasound, Southampton University Hospitals NHS Trust; Abhijit Bhattacharyya, General Practitioner, Solihull, West Midlands and Principal Clinical Fellow, Medical Education, University of Warwick; Sandra Bosman, Specialist Midwife for Multiple Pregnancy, Royal Victoria Infirmary, Newcastle-upon-Tyne; Leanne Bricker, Consultant in Fetal and Maternal Medicine, Liverpool Women's NHS Foundation Trust; Jane Denton, The Multiple Births Foundation (Lay member); Jane Hawdon, Consultant Neonatologist, University College London Hospitals NHS Foundation Trust; Mark Kilby, Professor of Fetal Medicine, University of Birmingham and Birmingham Women's Foundation Trust (GDG Chair); Frances Martin, Maternity Commissioner Programme Manager, West Sussex PCT, Goring-on-Sea, West Sussex; Kirstie McKenzie-McHarg, South Warwickshire General Hospitals NHS Foundation Trust (Lay member); Manjit Randhawa, Matron for Emergency Gynaecology Unit, Antenatal Ward and High Risk Teams in Midwifery, Guy's and St Thomas' NHS Foundation Trust, London; Baskaran Thilaganathan, Professor in Fetal Medicine, Director of Fetal Medicine Unit, St George's Hospital NHS Trust, London

Financial Disclosures/Conflicts of Interest

At the start of the guideline development process, all Guideline Development Group (GDG) members declared interests including consultancies, fee-paid work, share-holdings, fellowships and support from the healthcare industry. At all subsequent GDG meetings, members declared arising conflicts of interest, which were also recorded. The GDG members' declarations of interests are listed in Appendix B in the full version of the guideline (see the "Availability of Companion Documents" field).

Guideline Status

This is the current release of the guideline.

Guideline Availability
Availability of Companion Documents

The following are available:

  • Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. Quick reference guide. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 18 p. (Clinical guideline; no. 129). Electronic copies: Available in Portable Document Format (PDF) from the National Institute for Health and Clinical Excellence (NICE) Web site External Web Site Policy.
  • Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. Full guideline. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 235 p. (Clinical guideline; no. 129). Electronic copies: Available in PDF from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. Appendices. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. Various p. (Clinical guideline; no. 129). Electronic copies: Available in PDF from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. NICE pathway. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Jul. Various pages. (Clinical guideline; no. 126). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Clinical audit tool. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011. Various p. (Clinical guideline; no. 129). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Electronic audit tool. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011. Various p. (Clinical guideline; no. 129). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Costing report. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 19 p. (Clinical guideline; no. 129). Electronic copies: Available in PDF from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Costing template. Implementing NICE guidance. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. (Clinical guideline; no. 129). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Slide set. Implementing NICE guidance. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Nov. 21 p. (Clinical guideline; no. 129). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. Baseline assessment tool. Implementing NICE guidance. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011. (Clinical guideline; no. 129). Electronic copies: Available from the NICE Web site External Web Site Policy.
  • Multiple pregnancy. The management of twin and triplet pregnancies in the antenatal period. Implementation advice. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011. 22 p. (Clinical guideline; no. 129). Electronic copies: Available in PDF from the NICE Web site External Web Site Policy.
  • The guidelines manual 2009. London (UK): National Institute for Health and Clinical Excellence (NICE); 2009 Jan. Electronic copies: Available in PDF from the NICE Archive Web site External Web Site Policy.

In addition, Appendix D in the original guideline External Web Site Policy contains a sample schedule of antenatal appointments.

Patient Resources

The following is available:

  • Antenatal care for women who are pregnant with twins or triplets. Understanding NICE guidance. London (UK): National Institute for Health and Clinical Excellence (NICE); 2011 Sep. 16 p. (Clinical guideline; no. 129). Electronic copies: Available in Portable Document Format (PDF) from the National Institute for Health and Clinical Excellence (NICE) Web site External Web Site Policy. Also available in Welsh from the NICE Web site External Web Site Policy.

Please note: This patient information is intended to provide health professionals with information to share with their patients to help them better understand their health and their diagnosed disorders. By providing access to this patient information, it is not the intention of NGC to provide specific medical advice for particular patients. Rather we urge patients and their representatives to review this material and then to consult with a licensed health professional for evaluation of treatment options suitable for them as well as for diagnosis and answers to their personal medical questions. This patient information has been derived and prepared from a guideline for health care professionals included on NGC by the authors or publishers of that original guideline. The patient information is not reviewed by NGC to establish whether or not it accurately reflects the original guideline's content.

NGC Status

This summary was completed by ECRI Institute on February 24, 2012.

The National Institute for Health and Clinical Excellence (NICE) has granted the National Guideline Clearinghouse (NGC) permission to include summaries of their clinical guidelines with the intention of disseminating and facilitating the implementation of that guidance. NICE has not yet verified this content to confirm that it accurately reflects that original NICE guidance and therefore no guarantees are given by NICE in this regard. All NICE clinical guidelines are prepared in relation to the National Health Service in England and Wales. NICE has not been involved in the development or adaptation of NICE guidance for use in any other country. The full versions of all NICE guidance can be found at www.nice.org.uk External Web Site Policy.

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