Brief Introduction: Fetal growth restriction (FGR) contributes significantly to adverse fetal and neonatal outcome. The objective of this analysis was to investigate the perinatal outcomes of pregnancies complicated by early- and late-onset FGR. This is a secondary analysis of the Prospective Observational Trial to Optimise Paediatric Health in IUGR (PORTO) study.
Materials & Methods: A total of 1,200 fetuses with an EFW <10th centile between 24 + 0 and 36 + 6 weeks’ gestation were prospectively recruited. Sonographic parameters including multi-vessel Doppler assessment were recorded in addition to demographic, pregnancy and perinatal outcomes. Adverse pregnancy outcome was defined as a composite of intraventricular haemorrhage (IVH), periventricular leucomalacia (PVL), hypoxic ischaemic encephalopathy (HIE), necrotising enterocolitis (NEC), bronchopulmonary dysplasia (BPD), sepsis or death. A subgroup of pregnancies with EFW 95th centile, absent or reversed end diastolic flow) was divided into early- and late-onset FGR, defined as <34 and ≥34 weeks respectively. Statistical comparisons between early-and late onset FGR were made using Fisher’s exact test and logistic regression. A p-value <0.05 was considered statistically significant.
Clinical Cases or Summary Results: Of 1,116 pregnancies completing the study protocol, 512 met the inclusion criteria for this analysis. Early-and late-onset FGR accounted for 318 (62%) and 194 (38%) of cases respectively. Early-onset FGR was associated with lower birth weight at delivery, a higher neonatal intensive care admission and greater adverse composite perinatal outcome compared with late-onset FGR. Although adverse outcomes associated with early-onset FGR were associated with lower birth weight and earlier gestational age at delivery, these findings were not significant after adjusting for gestational age at delivery. Early-onset FGR was more commonly associated with gestational hypertension/preeclampsia (p = 0.13) and antihypertensive use (p = 0.019). To determine predictors of adverse perinatal outcome, a stepwise logistic regression analysis of all maternal demographic characteristics found that BMI >25kg/m2 (p = 0.002) in addition to (and independently of) advanced maternal age >35 years (p = 0.0489) were predictive of occurrence of FGR <34 weeks’ gestation (Table 1.)
Conclusions: Early-onset FGR is associated with adverse perinatal outcome. Although there were no differences in composite adverse pregnancy outcomes after adjustment for gestational age for early- versus late-onset FGR, perinatal mortality (1%) was reported in pregnancies ≤34 weeks’ gestation in our cohort. Risk factors for the development of early-onset FGR have been identified in this cohort as higher BMI and advanced maternal age. Results from this large prospective study further support the identification of maternal risk factors and intensive surveillance for FGR early in pregnancy.