Comparison of doppler studies with biophysical profile in prediction of perinatal outcome in patients with preeclampsia at Moi Teaching and Referral Hospital

Abstract

Background: Preeclampsia is a major direct cause of maternal mortality second only to hemorrhage with 50,000-60,000 preeclampsia related deaths worldwide annually. Preeclampsia has a global incidence of 5-14% with an incidence of 4-18% in developing countries. Incidence in Africa is 2-8% but has increased in recent years due to increase in risk factors. Preeclampsia is associated with several adverse maternal and fetal outcomes. In the fetus, it can lead to ischemic encephalopathy, growth restriction and the various sequelae of premature birth. Pregnancies complicated by preeclampsia require close fetal surveillance to guide management and improve outcomes. Poor Biophysical profile scores are associated with poor perinatal outcomes. Recent research has however shown that Doppler flow changes occur much earlier and can be used to time delivery with better perinatal outcomes including reduced rates of perinatal admissions, induction of labor, caesarean delivery and the odds of perinatal death. Objective: To determine and compare Doppler indices of the umbilical and middle cerebral arteries with biophysical profile scores in the prediction of perinatal outcomes in patients with preeclampsia at Moi Teaching and Referral Hospital. Methods: This was a hospital based cross sectional study conducted at the Radiology and Imaging and Reproductive Health departments at Moi Teaching and Referral Hospital from October 2016 to September 2017. Consenting patients with preeclampsia above 28 weeks gestation were consecutively sampled, questionnaires administered, scanned, followed up to delivery and outcomes documented. The ultrasounds were done by the principal investigator or a trained research assistant and later discussed with two consultant radiologists. Statistical analysis was done using STATA/MP version 13.0. Descriptive statistics were carried out for continuous variables using mean, median, standard deviation and interquartile range. Inferential statistics was carried out using Chi square test and data was presented in form of tables, graphs and pie charts. Results: One hundred and sixty five patients whose ages ranged from 15-42 years with an average of 29 years were included into the study. Majority (72.7%) presented between 28-34 weeks and 66.06% had preeclampsia with severe features. An abnormal outcome was seen in 86.4% of those who had abnormal BPP scores and abnormal BPP increased the Odds of poor outcome 4.95 times (p<0.001). An abnormal outcome was seen in 80% of those who had abnormal Doppler findings and abnormal Doppler findings increased the Odds of poor outcome 11.5 times (p<0.001). Poor perinatal outcomes included still birth, preterm birth, low birth weight and low APGAR score. MCA RI had no significant association with poor outcomes except when used as Cerebro-Placental Index (CPI). Conclusion: Abnormal BPP and Doppler findings were significantly associated with poor outcomes with Doppler being a better predictor. Recommendation: Doppler studies of both the UA and MCA including the CPI should be included in the prenatal ultrasound evaluation of pregnancies affected by preeclampsia.