Abstract

Evidence regarding first-trimester umbilical venous hemodynamics and subsequent perinatal morbidity is limited. We evaluated the associations of first-trimester umbilical venous Doppler parameters with neonatal intensive care unit (NICU) admission and preterm birth in singleton pregnancies. This prospective cohort study included 90 pregnancies examined at 11+0 to 13+6 weeks. Time-averaged maximum velocity (TAMXV), umbilical vein diameter, vessel cross-sectional area, and umbilical venous blood flow (UVBF) were measured during routine first-trimester ultrasonography; pregnancy-associated plasma protein-A, free beta-human chorionic gonadotropin (free β-hCG), and nuchal translucency were also recorded. Group comparisons, logistic regression, and receiver operating characteristic analyses were performed. NICU admission occurred in 11 of 87 neonates with available outcome data, and preterm birth occurred in 10 of 90 pregnancies. First-trimester biochemical and umbilical venous Doppler parameters did not differ significantly by NICU admission or preterm birth status. In univariable analysis, higher free β-hCG multiples of the median (MoM) (odds ratio [OR], 2.64; 95% confidence interval [CI], 1.21–5.76; p=.015) and higher TAMXV (OR, 1.16; 95% CI, 1.00–1.33; p=.043) were associated with NICU admission. Neither association remained significant in the primary exploratory multivariable model. In a sensitivity analysis adjusted for gestational age at delivery, TAMXV was attenuated, whereas free β-hCG MoM remained associated with NICU admission (adjusted OR, 2.23; 95% CI, 1.03–4.81; p=.041). TAMXV and UVBF showed limited discrimination for NICU admission and preterm birth. No significant adjusted associations were observed between first-trimester umbilical venous Doppler parameters and either outcome. These findings are exploratory and require confirmation in larger prospective studies.

Key words: First trimester, umbilical vein, Doppler ultrasonography, neonatal intensive care unit, preterm birth, pregnancy