In addition to these evidence-based recommendations, the guideline development group also identifies points of best clinical practice in the original guideline document.
Classification of evidence levels (1++ to 4) and grades of recommendations (A-D) are defined at the end of the "Major Recommendations" field.
What Are the Risk Factors for a Small-or-Gestational-Age (SGA) Fetus/Neonate? What is the Optimum Method of Screening for the SGA Fetus/Neonate and Care of "At Risk" Pregnancies?
B - Women who have a major risk factor (Odds Ratio [OR] >2.0) should be referred for serial ultrasound measurement of fetal size and assessment of wellbeing with umbilical artery Doppler from 26–28 weeks of pregnancy (Appendix 1 of the original guideline document).
Biochemical Markers Used for Down Syndrome (DS) Screening
B - 2nd trimester DS markers have limited predictive accuracy for delivery of a SGA neonate.
Uterine Artery Doppler
A - In a low risk population uterine artery Doppler has limited accuracy to predict a SGA neonate and use in the 2nd trimester has shown no benefit to mother or baby. Use of uterine artery Doppler in this population is not justified.
A - In high risk populations uterine artery Doppler at 20–24 weeks of pregnancy has a moderate predictive value for a severely SGA neonate.
C - In women with an abnormal uterine artery Doppler at 20–24 weeks of pregnancy, subsequent normalisation of flow velocity indices is still associated with an increased risk of a SGA neonate. Repeating uterine artery Doppler is therefore of limited value.
Fetal Echogenic Bowel
C - Serial ultrasound measurement of fetal size and assessment of wellbeing with umbilical artery Doppler should be offered in cases of fetal echogenic bowel.
C - Abdominal palpation has limited accuracy for the prediction of a SGA neonate and thus should not be routinely performed in this context.
B - Serial measurement of symphysis fundal height (SFH) is recommended at each antenatal appointment from 24 weeks of pregnancy as this improves prediction of a SGA neonate.
What Is the Optimum Method of Diagnosing a SGA Fetus and Fetal Growth Restriction (FGR)?
A - Fetal abdominal circumference (AC) or estimated fetal weight (EFW) <10th centile can be used to diagnose a SGA fetus.
C - Use of a customised fetal weight reference may improve prediction of a SGA neonate and adverse perinatal outcome. In women having serial assessment of fetal size, use of a customised fetal weight reference may improve the prediction of normal perinatal outcome.
A - Routine measurement of fetal AC or EFW in the 3rd trimester does not reduce the risk of a SGA neonate nor does it improve perinatal outcome. Routine fetal biometry is thus not justified.
C - Change in AC or EFW may improve the prediction of wasting at birth (neonatal morphometric indicators) and adverse perinatal outcome suggestive of FGR.
C - When using two measurements of AC or EFW to estimate growth velocity, they should be at least 3 weeks apart to minimize false–positive rates for diagnosing FGR. More frequent measurements of fetal size may be appropriate where birth weight prediction is relevant outside of the context of diagnosing SGA/FGR.
What Investigations Are Indicated in SGA Fetuses?
C - Offer a referral for a detailed fetal anatomical survey and uterine artery Doppler by a fetal medicine specialist if severe SGA is identified at 18–20 week scan.
C - Karyotyping should be offered in severely SGA fetuses with structural anomalies and in those detected before 23 weeks of gestation, especially if uterine artery Doppler is normal.
C - Serological screening for congenital cytomegalovirus (CMV) and toxoplasmosis infection should be offered in severe SGA.
C - Uterine artery Doppler has limited accuracy to predict adverse outcome in SGA fetuses diagnosed during the 3rd trimester.
What Interventions Should Be Considered in the Prevention of SGA Fetuses/Neonates?
C - Antiplatelet agents may be effective in preventing SGA birth in women at high risk of preeclampsia although the effect size is small.
A - In women at high risk of preeclampsia antiplatelet agents should be commenced at or before 16 weeks of pregnancy.
A - There is no consistent evidence that dietary modification, progesterone or calcium prevent SGA birth. These interventions should not be used for this indication.
A - Interventions to promote smoking cessation may prevent SGA birth. The health benefits of smoking cessation indicate that these interventions should be offered to all women who are pregnant and smoke.
D - Antithrombotic therapy appears to be a promising therapy for preventing SGA birth in high risk women. However, there is insufficient evidence, especially concerning serious adverse effects, to recommend its use.
What Interventions Should Be Considered in the Preterm SGA Fetus?
C - Women with a SGA fetus between 24+0 and 35+6 weeks of gestation, where delivery is being considered, should receive a single course of antenatal corticosteroids.
What is the Optimal Method and Frequency of Fetal Surveillance in a SGA Infant and What Is/Are the Optimal Test/s to Time Delivery?
Umbilical Artery Doppler
A - In a high–risk population, the use of umbilical artery Doppler has been shown to reduce perinatal morbidity and mortality. Umbilical artery Doppler should be the primary surveillance tool in the SGA fetus.
B - When umbilical artery Doppler flow indices are normal it is reasonable to repeat surveillance every 14 days.
A - CTG should not be used as the only form of surveillance in SGA fetuses.
A - Interpretation of the CTG should be based on short term fetal heart rate variation from computerised analysis.
Amniotic Fluid Volume
A - Interpretation of amniotic fluid volume should be based on single deepest vertical pocket.
Biophysical Profile (BPP)
A - BPP should not be used for fetal surveillance in preterm SGA fetuses.
Middle Cerebral Artery (MCA) Doppler
B - In the preterm SGA fetus, MCA Doppler has limited accuracy to predict acidaemia and adverse outcome and should not be used to time delivery.
C - In the term SGA fetus with normal umbilical artery Doppler, an abnormal middle cerebral artery Doppler (pulsatility index [PI] <5th centile) has moderate predictive value for acidosis at birth and should be used to time delivery.
Ductus Venosus (DV) and Umbilical Vein (UV) Doppler
A - DV Doppler has moderate predictive value for acidaemia and adverse outcome.
What Is the Optimal Gestation To Deliver the SGA Fetus?
C - If MCA Doppler is abnormal delivery should be recommended no later than 37 weeks of gestation.
A - In the SGA fetus detected after 32 weeks of gestation with normal umbilical artery Doppler, a senior obstetrician should be involved in determining the timing and mode of birth of these pregnancies. Delivery should be offered at 37 weeks of gestation.
How Should the SGA Fetus Be Delivered?
B - In the SGA fetus with normal umbilical artery Doppler or with abnormal umbilical artery PI but end–diastolic velocities present, induction of labour can be offered but rates of emergency caesarean section are increased and continuous fetal heart rate monitoring is recommended from the onset of uterine contractions.
Grades of Recommendations
A - At least one meta-analysis, systematic review or randomised controlled trial rated as 1++, and directly applicable to the target population; or
A systematic review of randomised controlled trials or a body of evidence consisting principally of studies rated as 1+, directly applicable to the target population and demonstrating overall consistency of results
B - A body of evidence including studies rated as 2++ directly applicable to the target population, and demonstrating overall consistency of results; or
Extrapolated evidence from studies rated as 1++ or 1+
C - A body of evidence including studies rated as 2+ directly applicable to the target population and demonstrating overall consistency of results; or
Extrapolated evidence from studies rated as 2++
D - Evidence level 3 or 4; or
Extrapolated evidence from studies rated as 2+
Classification of Evidence Levels
1++ High-quality meta-analyses, systematic reviews of randomised controlled trials or randomised controlled trials with a very low risk of bias
1+ Well-conducted meta-analyses, systematic reviews of randomised controlled trials or randomised controlled trials with a low risk of bias
1– Meta-analyses, systematic reviews of randomised controlled trials or randomised controlled trials with a high risk of bias
2++ High-quality systematic reviews of case–control or cohort studies or high-quality case–control or cohort studies with a very low risk of confounding, bias, or chance and a high probability that the relationship is causal
2+ Well-conducted case–control or cohort studies with a low risk of confounding, bias, or chance and a moderate probability that the relationship is causal
2– Case–control or cohort studies with a high risk of confounding, bias, or chance and a significant risk that the relationship is not causal
3 Non-analytical studies, e.g., case reports, case series
4 Expert opinion