Umbilical artery Doppler Indices in second and third trimesters in normal singleton pregnancy at nnamdi azikiwe university teaching hospital nnewi, Nigeria

Abstract

Background: Doppler ultrasound was introduced into clinical obstetric practice over 20 years ago. Common obstetric complications such as pre-eclampsia and intra-uterine growth restriction (IUGR) originate in abnormal placental vasculature development, reflected in abnormal Doppler velocimetry. Objectives: To determine the pulsatility index (PI), resistivity index (RI), systolic/diastolic ratio(S/D), end diastolic velocity (EDV), and peak systolic velocity (PSV) of the umbilical artery of normal singleton pregnancy during the second and third trimesters in Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria. Materials and Methods: A prospective longitudinal study of 141 patients was conducted at 21–25 weeks (second trimester) and 31–35 weeks (third trimester) gestation. An ultrasound machine with Doppler capability fitted with a curvilinear transducer with a frequency of 3.5–5.0MHZ was used to measure the PI, RI, S/D ratio, EDV, and PSV of the participants. Results: The second and third-trimester uterine artery Doppler indices of the participants were, respectively: PI = 1.29 ± 0.36, versus 0.94 ± 0.24 (P <0.001), RI = 0.73 ± 0.10, versus 0.60 ± 0.10 (P < 0.001), S/D ratio = 3.68 ± 2.36, versus 2.29 ± 0.63 (P < 0.001), PSV = 48.52 ± 18.28, versus 65.24 ± 24.01 (P < 0.001), and EDV = 315.23 ± 9.11, versus 0.58 ± 14.43 (P < 0.001). The PI, RI, and S/D ratio values decrease between the second to third trimesters while the PSV and EDV values increase between the second to third trimesters. Conclusion: The study has established the baseline reference values for normal singleton pregnancies in the study population and the Doppler indices of women with high-risk pregnancies could be compared with them.

Keywords

• doppler indices
• pregnancy
• second
• third trimester
• umbilical artery