Associations of First-Trimester Aneuploidy Markers With Neonatal Anthropometry and Small for Gestational Age/Large for Gestational Age Outcomes

Background: Early detection of fetal developmental abnormalities can allow for necessary precautions to be taken to reduce risks that may arise during and after birth. This study aimed to investigate the association between first-trimester aneuploidy screening markers—pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotropin (fβ-hCG), and nuchal translucency (NT)—and neonatal anthropometric measurements (weight, length, and head circumference). It also evaluated their predictive value for subsequent fetal growth abnormalities, including small for gestational age (SGA) and large for gestational age (LGA) births. Methods: This retrospective study included 422 singleton pregnant women and their newborns. First-trimester NT, fβ-hCG, and PAPP-A multiple of the median (MoM) values were compared among mothers who delivered SGA, appropriate for gestational age (AGA), and LGA infants. Correlations between these markers and neonatal percentiles for weight, length, and head circumference were also examined. Results: Mothers of SGA neonates had significantly lower PAPP-A and fβ-hCG MoM values than mothers of AGA or LGA neonates (p < 0.05). Receiver operating characteristic (ROC) analysis demonstrated moderate discriminatory performance for the identification of pregnancies at increased risk of SGA, with an area under the curve (AUC) of 0.687 for fβ-hCG MoM (p < 0.001) and 0.674 for PAPP-A MoM (p = 0.001). Spearman correlation analysis showed that PAPP-A MoM was positively correlated with neonatal birth weight (r = 0.133, p = 0.006) and length percentiles (r = 0.151, p = 0.002). fβ-hCG MoM was also positively correlated with neonatal weight (r = 0.151, p = 0.002), length (r = 0.114, p = 0.019), and head circumference percentiles (r = 0.104, p = 0.032). Correlation analysis revealed no significant association between NT MoM and neonatal anthropometric measurements. In multivariable logistic regression analysis, lower first-trimester PAPP-A MoM (adjusted odds ratio [aOR]: 2.51) and fβ-hCG MoM (aOR: 2.95) remained independently associated with SGA, whereas NT MoM did not. Conclusions: First-trimester PAPP-A and fβ-hCG values were significantly lower in mothers who delivered SGA infants and showed moderate discriminatory ability for the identification of pregnancies at increased risk of SGA. In addition, first-trimester PAPP-A and fβ-hCG levels were correlated with neonatal birth weight and length, and first-trimester fβ-hCG levels were also correlated with neonatal head circumference. In contrast, first-trimester NT was not associated with neonatal anthropometric outcomes.