Fetal Growth Restriction Management

Diagnostic Evaluation

The American College of Obstetricians and Gynecologists recommends performing a detailed obstetrical ultrasound examination immediately for fetuses with a head circumference at the 1st percentile at 32 weeks, as up to 20% of early-onset FGR cases are associated with fetal or chromosomal abnormalities 1, 2
Prenatal diagnostic testing with chromosomal microarray analysis is recommended for unexplained isolated FGR diagnosed before 32 weeks, as it provides a 4-10% incremental yield over standard karyotype 1, 3
If fetal malformation or polyhydramnios is present alongside the severe head circumference restriction, chromosomal microarray testing is strongly recommended regardless of gestational age 1, 2

A head circumference at the 1st percentile represents severe FGR, which is associated with a 3-fold to 7-fold increased risk of stillbirth compared to fetuses between the 5th-10th percentile 3
Severe FGR with estimated fetal weight less than the 3rd percentile is associated with increased risk of adverse perinatal outcomes independent of umbilical artery Doppler findings 3

The American College of Obstetricians and Gynecologists recommends initiating serial umbilical artery Doppler assessment immediately to evaluate for placental insufficiency and deterioration 1, 2
Weekly umbilical artery Doppler evaluation is recommended for severe FGR, with increased frequency if absent end-diastolic velocity is detected 1, 2
If reversed end-diastolic velocity is detected, hospitalization is required with cardiotocography at least 1-2 times daily, administration of antenatal corticosteroids, and consideration of delivery 1, 2

For severe FGR with estimated fetal weight less than the 3rd percentile and normal umbilical artery Doppler, delivery at 37 weeks is recommended 1, 2
If absent end-diastolic velocity is detected, delivery at 33-34 weeks gestation is recommended 1
If reversed end-diastolic velocity is detected, delivery at 30-32 weeks gestation is recommended 1

The American College of Obstetricians and Gynecologists recommends monitoring closely for development of hypertensive disorders of pregnancy, as maternal hypertension is present in 50-70% of early-onset FGR cases and is one of the most important independent determinants of poor outcomes 2
Maternal hypertension significantly shortens the interval to delivery and results in earlier gestational age at birth with lower birthweights 2

The Royal College of Obstetricians and Gynaecologists defines Fetal Growth Restriction (FGR) as an ultrasonographic estimated fetal weight (EFW) or abdominal circumference (AC) below the 10th percentile for gestational age, with population-based fetal growth references, such as Hadlock, used to determine fetal weight percentiles 4
Severe FGR is defined as EFW less than the 3rd percentile, according to the American College of Obstetricians and Gynecologists 4, 5

A detailed obstetrical ultrasound examination should be performed with early-onset FGR (<32 weeks of gestation) as up to 20% of cases are associated with fetal or chromosomal abnormalities, as recommended by the American College of Obstetricians and Gynecologists 4, 6
Pregnant women should be offered prenatal diagnostic testing with chromosomal microarray analysis (CMA) when FGR is detected with fetal malformation, polyhydramnios, or both, regardless of gestational age, according to the American College of Obstetricians and Gynecologists 4

Once FGR is diagnosed, serial umbilical artery Doppler assessment should be performed to assess for deterioration, with the frequency of assessment depending on the severity of FGR and the presence of abnormal Doppler findings, as recommended by the American College of Obstetricians and Gynecologists 4, 7
For severe FGR (EFW <3rd percentile) or decreased end-diastolic velocity, weekly umbilical artery Doppler evaluation is recommended, according to the American College of Obstetricians and Gynecologists 4, 5

For FGR with normal umbilical artery Doppler (EFW 3rd-10th percentile), delivery at 38-39 weeks is recommended, according to the American College of Obstetricians and Gynecologists 4, 8
For FGR with decreased diastolic flow (but without AEDV/REDV) or severe FGR (EFW <3rd percentile), delivery at 37 weeks is recommended, as suggested by the American College of Obstetricians and Gynecologists 4, 8

For pregnancies with FGR complicated by AEDV/REDV, cesarean delivery should be considered based on the entire clinical scenario, according to the American College of Obstetricians and Gynecologists 4, 8
Antenatal corticosteroids should be administered if delivery is anticipated before 33 6/7 weeks of gestation, as recommended by the American College of Obstetricians and Gynecologists 4, 8

The American College of Radiology recommends that, within 24–48 hours of identifying a possible fetal growth restriction, a comprehensive transabdominal ultrasound be performed. This should include fetal biometry, amniotic‑fluid volume measurement, umbilical‑artery Doppler velocimetry, a detailed anatomic survey, and placental evaluation. 9
According to the American College of Radiology, the ultrasound‑based placental assessment must examine placental location, appearance, and any structural abnormalities to help determine the etiology of growth restriction. 10

The American Family Physician guideline states that any amount of bacteriuria detected during pregnancy requires antimicrobial treatment in line with current standards of care, even when the patient is asymptomatic, to prevent maternal and neonatal complications. 11
The same guideline advises that a repeat urine culture should be obtained after completion of therapy to confirm eradication of the organism. 11