Assessment of fetal growth trajectory identifies infants at high risk of perinatal mortality

Abstract

ObjectiveTo analyze perinatal risks associated with three distinct scenarios of fetal growth trajectory in the latter half of pregnancy compared with a referent group.MethodsThis cohort study included women with singleton pregnancies that birthed between 32+0 and 41+6 gestational weeks and had two or more ultrasound scans at least four weeks apart from 18+0 weeks. We evaluated three different scenarios of fetal growth against a referent, defined as appropriate for gestational age‐sized fetuses with appropriate forward growth trajectories. The comparator growth trajectories were categorized as Group 1: Small for gestational age (SGA) fetuses (EFW or AC <10th centile) with appropriate forward growth; Group 2: Decreased growth trajectory fetuses (decrease of ≥50 centiles) with EFW or AC ≥10th centile (i.e., non‐SGA) at their final scan; and Group 3: Decreased growth trajectory fetuses with EFW or AC <10th centile (i.e., SGA) at their final scan. The primary outcomes were perinatal mortality (stillbirth or neonatal death). Secondary outcomes included stillbirth, birth of an SGA infant, preterm birth, emergency cesarean section (CS) for non‐reassuring fetal status (NRFS), and composite severe neonatal morbidity. Associations were analyzed using logistic regression.ResultsThe final study cohort comprised 5319 pregnancies. Compared to the referent group, the adjusted odds of perinatal mortality were significantly increased in Group 2 (odds ratio [OR] 4.00, 95%CI 1.36–11.22) and Group 3 (OR 7.71, 95%CI 2.39–24.91). Only Group 3 had increased odds of stillbirth (OR 5.69, 95%CI 1.55–20.93). In contrast, infants in Group 1 did not have significantly increased odds of demise. The odds of an SGA infant at birth increased in all three groups but were highest in Group 1 (OR 111.86, 95%CI 62.58–199.95) and Group 3 (OR 40.63, 95%CI 29.01–56.92). In both groups, more than 80% of infants were born SGA, and nearly half had a birth weight <3rd centile. Likewise, the odds of preterm birth were increased in all three groups, being the highest in Group 3 with an OR of 4.27 (3.23–5.64). Lastly, the odds of severe neonatal morbidity were increased in Groups 1 and 3, whereas the odds of emergency CS for NRFS were only increased in Group 3.ConclusionsAssessing the fetal growth trajectory in the latter half of pregnancy can help identify infants at increased risk of perinatal mortality and birth weight <3rd centile for gestation.This article is protected by copyright. All rights reserved.