The Association Between High Body Mass Index and Pregnancy Outcomes Among Women Who Delivered at Webuye County Hospital in 2019: a Retrospective Cohort Study

Abstract

Background: High BMI is associated with adverse pregnancy outcomes, high rate of caesarean sections, and high health care costs in the developed world, but its association with adverse pregnancy outcomes in Kenya has not been studied comprehensively. Objectives: To determine the association between high BMI and adverse pregnancy outcomes at Webuye County Hospital (WCH) in 2019 Methodology: A retrospective cohort study was carried out at Webuye County Hospital (WCH). The hospital charts of 178mothers with high BMI (exposed group) were compared with 172who had normal BMI (non-exposed group). Participants were recruited before 20 weeks of gestation aged 18-50 years with BMI >18.5kg/m2. Women with BMI <18.5kg/m2 and multiple gestations were excluded. Data was analyzed using SPSS version 23. Maternal and perinatal outcomes such as hypertensive disorders of pregnancy, preterm and post term delivery, mode of delivery, poor fifth minute Apgar score of below 7, respiratory distress syndrome, large for gestation age, small for gestation age, and mortality were compared using the Chi square test and Man-Whitney U test. Relative risk was the measure of association. P value <0.05 was significant. Results: Three hundred and fifty (350) comprising women with high BMI (178) and normal BMI (172) were recruited and data compared. Demographic factors of women with high and normal BMI were similar. The risk of hypertensive disorders (RR=1.18, 95% CI), caesarian sections (RR=1.19, 95% CI=0.91-1.49, P=0.187), and post-partum hemorrhage (RR=1.31, 95% CI=0.58-1.84, P=0.435) were higher among overweight and obese women compared to those with a normal BMI but the difference were not statistically significant. Poor Apgar at 5 minutes was statistically significantly higher among women who had a high BMI (2.3%) compared to normal BMI (0.0%) (P=0.048). However, after adjusting for demographic and reproductive characteristics, the difference was not significant (0.985).Risk of preterm births (RR=0.97, 95% CI=0.72-1.25, P=0.873), stillbirths (RR=0.97, 95% CI=0.72-1.25, P=0.873), and Large for gestation age (RR=0.65, 95% CI=0.18-1.38, P=0.386) was lower with higher BMI compared to normal BMI but not significantly. Conclusion: High BMI compared to normal BMI was not associated with adverse maternal but was marginally associated with adverse perinatal outcomes, predominantly low Apgar score at 5 minutes Key Words: Body Mass Index, Maternal Outcomes, perinatal Outcomes