A Comparison of the Umbilical Artery Doppler Indices between Pregnancies with Advanced and Normal Maternal Age in the Second Trimester

Objective: To compare the pulsatile index (UA-PI), resistance index (UA-RI), and systolic/diastolic ratio (UA-S/D) of the umbilical artery between pregnant women with advanced maternal age (AMA) and normal maternal age. Materials and Methods: Participants were pregnant women who attended antenatal care at the maternal-fetal medicine unit at Bhumibol Adulyadej Hospital, Royal Thai Air Force, Bangkok, Thailand. The present study was conducted between February and December 2022. Participants who met inclusion criteria were classified as study for the patients aged 35 years and older, and control groups for the patients younger than 35 years old. All participants underwent ultrasonography for umbilical artery Doppler velocimetry measurement including UA-PI, UA-RI, and UA-S/D. Demographic characters of both study and control groups were included for statistical calculation. Results: Five hundred pregnant women with gestational age between 18 and 24 weeks were enrolled. The mean age of the study and the control group were 37.9 and 26.0 years, respectively. Participants in the study group have higher BMI than the control group. The study and the control group had comparable diastolic and systolic blood pressure. The mean (standard deviation) of UA-PI, UA-RI, and S/D ratio of the study/control group were 1.33±0.21/1.27±0.22, 0.77±0.1/0.74±0.09, and 4.24±0.98/3.95±0.97, respectively, with statistical significance. The study group had a significantly higher number of large for gestational age (LGA), pregnancy induced hypertension (PIH), and gestational diabetes mellitus (GDM) than the control group. Conclusion: AMA pregnancy had higher UA-PI, UA-RI, UA-S/D, incidence of PIH, GDM, and LGA than those age less than 35 years. Keywords: Advanced maternal age; Umbilical artery Doppler indices; Second trimester