ABSTRACT
Background: Reproductive health has a direct relationship with perinatal health/child survival, hence interventions during pregnancy have efficacious impact on perinatal outcome. The increasing perinatal mortality indices can be reduced by Doppler intervention in pregnancies complicated by medical disorders such as pre-eclampsia, intrauterine growth restriction where blood flow to the uterus and placenta has been found to be decreased. However, a normal Doppler pattern obtained in our environment from indigenous normal pregnant women, is necessary for proper interpretation when used in complicated pregnancies in a bid to prevent perinatal death. Improved perinatal survival provided by employing Doppler assessment of the umbilical arteries, is based on indigenous values obtained from normal pregnancies in specific geographical regions; as advocated from previous studies. Providing timely opportunity to ascertain the level of fetal compromise with timely intervention and hence better improvement of fetal outcome/ perinatal mortality indices.
Aim: To ascertain the pattern of fetal umbilical artery Doppler velocimetry in normal pregnancy, as a reference guide to reduce perinatal mortality.
Methods: This prospective longitudinal study conducted at the Obstetrics and Gynecology Department of University of Benin Teaching Hospital, Benin City, included 166 women booked for ultrasound between 30 to 40 weeks of gestation using the systematic random sampling technique. Doppler analysis of the umbilical artery was done two weekly. The data obtained was analyzed using IBM Statistical Package for Social Sciences version 22 (R) software (SPSS Inc. Chicago, IL, USA). The primary outcome measure was the pattern of discriminatory values of PI & RI with advancing gestation. The range of PI & RI in specified gestational age was the secondary outcome measure.
Results The PI and RI pattern decreased with advancing gestational age in the normotensives.
The range of values of PI and RI in specified gestation were 0.49- 0.99 and 0.49- 0.79 respectively. There was negative correlation between PI and RI and gestational age. Parity (≤4) and gestational age were statistically significantly associated with the declining trend of PI and RI.
Conclusion There is a decreasing pattern in PI & RI normotensives with increasing gestational age. Findings will aid management of pregnancies at risk when a deviation from this pattern is noted and hence reduce perinatal mortality.
Key words: Pulsatility index, Resistivity index, Doppler.
