Fetal Growth Restriction (FGR)

FGR has been defined as <10th percentile weight for gestational age on a singleton growth curve, as this establishes the diagnosis as being small for gestational age. When a fetus <10th percentile weight for gestational age is identified, the fetal growth and fetal physiology is monitored over time. Customized growth curves account for nonpathologic maternal factors that affect birth weight. This allows interpretation of estimated fetal weight in the context of the individual fetus growth potential, rather than against a population-based birth weight distribution. There are multiple causes and risk factors for FGR which pregnant women should be asked and screened for. Serial fundal height measurements at each prenatal visit help us to suspect the women low risk for FGR but in high risk women ultrasound exam once or twice in 3rd trimester to assess the fetal weight is mandatory in addition to serial fundal height measurement. Stillbirth, neonatal death, neonatal morbidity, and abnormal neurodevelopmental outcome are more common in growth-restricted fetuses than in those with normal growth. The prognosis worsens with early onset and increasing severity of growth restriction. The long term effects include later development of obesity, metabolic dysfunction, insulin sensitivity, type 2 diabetes, cardiovascular and renal diseases (coronary heart disease, hypertension, chronic kidney disease). When FGR is diagnosed serial ultrasound evaluation of fetal growth (92-4 weeks), fetal behavior (Biophysical profile [BPP] or NST & AF)and fetal vessels Doppler velocimetry is performed to assess the fetal wellbeing. Women with pregnancies complicated by FGR may maintain normal activities and are usually monitored as outpatients. Hospitalization is considered for selected women who need daily or more frequent maternal or fetal assessment (eg, daily BPP score because of absent or reversed diastolic flow). Hospitalization provides convenient access for daily fetal testing and allows prompt evaluation and intervention. One course of antenatal corticosteroids between 24 -34 weeks of gestation in the week before delivery is expected. For fetuses less than 32 weeks of gestation, magnesium sulfate is given before delivery for neuroprotection. The time of delivery of the growthrestricted fetus is based on a combination of factors, including gestational age, Doppler results, BPP score, the presence or absence of risk factors for, or signs of, uteroplacental insufficiency such as preeclampsia. The goal is to maximize fetal maturity and growth while minimizing the risks of fetal or neonatal mortality, shortterm and long-term morbidity. It is important to optimize the timing of delivery, perform continuous intrapartum fetal monitoring to detect nonreassuring fetal heart rate patterns suggestive of progressive hypoxia during labor, provide skilled neonatal care in the delivery room and measure umbilical cord blood PH to establish baseline neonatal status. Cesarean delivery for fetal indications is more common when growth restriction is present.