Fetal growth trajectories and neonatal outcomes: A French population‐based study

OBJECTIVE: This study assesses whether fetal growth trajectories are associated with neonatal outcomes. METHODS: The study population included 8537 singleton liveborn infants from the 2021 French National Perinatal Survey. Fetal growth trajectories were assessed between second and third trimester routine ultrasounds and between the third trimester ultrasound and birth, and classified for each period as constant (C, fetal weight variation <±1 standard deviation [SD]), accelerated (A, ≥ 1 SD), or declining (D, ≤ -1 SD). Seven combined trajectory groups were defined over both periods: CC, AC, CA, AA, DC, CD, and DD. A composite neonatal outcome included 5-min Apgar score < 7, pH < 7.10, birth resuscitation, neonatal transfer, or death. Adjusted odds ratios (aOR) for potential confounders with 95% confidence intervals (CI) were estimated for the full cohort and by small for gestational age (SGA, birthweight < 10th centile) status. RESULTS: The fetal trajectory was constant (CC), declining (DC, CD, DD) or accelerated (AC, CA, AA) for 54%, 27%, and 18% of fetuses, respectively. In the overall population, the risk of poor neonatal outcomes was higher in the CD group (aOR, 1.6 [95% CI, 1.3-2.0]) and the DD group (aOR, 2.0 [95% CI, 1.3-3.2]). This risk was also increased in the DD group (aOR, 3.7 [95% CI, 1.8-7.9]) among SGA births and in the CD group (aOR, 1.5 [95% CI, 1.2-2.0]) among non-SGA births. CONCLUSION: Declining fetal growth trajectories throughout and during the third trimester of pregnancy were associated with an increased risk of poor neonatal outcomes among both SGA and non-SGA infants.