126. Sex and growth specific characteristics of small for gestational age neonates: A prospective cohort study

Abstract

Introduction Male bearing pregnancies and asymmetric fetal growth are associated with preeclampsia (PE). However, this has not been studied in small for gestational age (SGA) neonates, a group that is also associated with PE. Objective To provide insight regarding risk factors and differences in neonatal outcome for SGA neonates based on sex and growth symmetry. Methods Data from the Screening for Pregnancy Endpoints (SCOPE) study were used with 5628 nulliparous participants, of which 633 pregnancies were complicated with SGA and 3376 women had uncomplicated pregnancies. SGA pregnancies were grouped based on fetal sex (male/female) and growth symmetry [ponderal index below (asymmetric) and above (symmetric) the 10th percentile for gestation]. Association between risk factors for SGA, SGA subgroups and uncomplicated pregnancies were assessed with multinominal analyses. Results Of all asymmetric neonates, 24.2% were SGA, while 7.4% of all symmetric neonates were SGA. Of all SGA neonates, 45.8% showed asymmetric growth, while 5.5% of neonates with a customised birthweight >90th percentile (p 90th percentile) umbilical Doppler resistance index (RI) at 20 weeks’ gestation was more common in SGA females (9.6% vs 17.8% p = 0.003) but did not differ between symmetric and asymmetric SGA neonates. The presence of abnormal uterine artery Doppler RI at 20 weeks’ gestation did not differ between SGA subgroups. In each SGA subgroup PE incidence was increased (28.2% in symmetric SGA, 26.1% in asymmetric SGA, 27.2% in SGA male and 25.3% in SGA female bearing pregnancies) compared to non-SGA pregnancies (4.2%). The incidence of PE did not differ between SGA subgroups. Discussion A quarter of asymmetric neonates are SGA. Asymmetric SGA associates with male neonates. In contrast with literature, PE was associated with both symmetric and asymmetric growth in SGA neonates.