(418) Perinatal outcomes of FGR-infants ≥26 weeks and <500g compared to <26weeks neonates with paired birthweight.

To investigate the perinatal survival of fetal growth restriction (FGR) with birthweight (BW) < 500 grams beyond 26⁺⁰ weeks and compare their outcome with non-FGR neonates paired for BW born prior to 26⁺⁰ weeks.

Study Design:

Retrospective study on data from the U.S. National Center for Health Statistics birth certificate data 2011-to-2023. Singleton pregnancies with delivery of a neonate weighting < 500 grams between 22⁺⁰ and 31⁺⁶ weeks were included. For each infant, the corresponding birthweight percentile was calculated according to the Fenton growth curve. Fetuses born prior to 26⁺⁰ weeks with BW < 3rd percentile were excluded.

Results:

18230 cases were included, of whom 5752 were FGR with BW < 500 grams born beyond 26⁺⁰ weeks. Their perinatal survival rate declined with advancing gestation from 26 to 31 weeks (66.8% vs 44.5%, respectively, p< 0.01) (Figure 1). Outcome comparison between cases of FGR with BW < 500 grams born >26⁺⁰ weeks and non-FGR with BW < 500 grams < 26⁺⁰ weeks showed a lower rate of chorioamnionitis (2.1% vs 6.9%, p=0.01) and vaginal delivery (28% vs 68%, p< 0.01) and a higher frequency of antenatal corticosteroids administration (33.7% vs 21.5%, p< 0.01) and preeclampsia (23.9% vs 0.8%, p< 0.01) in FGR neonates born beyond 26⁺⁰ weeks. The overall survival rate was higher for FGR neonates born beyond 26⁺⁰ weeks compared to non-FGR neonates born prior to 26⁺⁰ weeks (63.4% vs 38.1%, p< 0.01).

Conclusion:

In FGR with BW < 500 grams beyond 26⁺⁰ weeks, the perinatal survival rate is inversely correlated with the gestational age. However, this group shows an overall higher survival rate compared to non-FGR neonates born below 26 weeks with paired birthweight.