First trimester body mass index and pregnancy outcomes: A 3-year retrospective study from a low-resource setting

Abstract

Background: Extremes of body mass index (BMI) are associated with adverse pregnancy outcomes. This study was conducted to determine the prevalence of obesity and underweight among women in their first trimester and evaluate the impact of first trimester BMI on pregnancy outcome. Patients and Methods: Pregnant women who booked in the first trimester of pregnancy in Aminu Kano Teaching Hospital, and met the inclusion criteria, were studied retrospectively for a 3-year period from January 2012 to December 2014. Their booking BMIs were calculated and categorized using WHO classes. Pearson's Chi square test was used for all categories. Results: A total of 649 pregnant women booked in the first trimester during the study period, out of which 502 were eligible for the study. Of this, 99 women were obese and 57 were underweight giving the prevalence of obesity and underweight in first trimester of pregnancy as 15.3% and 8.8% respectively. Maternal outcomes mostly associated with obesity and overweight were hypertensive disorders in pregnancy (42.0%), gestational diabetes mellitus (41.3%), increased abdominal and instrumental delivery (38.6%), as well as third and fourth degree perineal tears (71.4%). Neonatal outcomes were low birth weight and fetal macrosomia (57.8%), preterm delivery and prolonged pregnancy (46.0%). The underweight group had a favorable outcome in majority of the outcomes assessed. Conclusion: Obesity in pregnancy is relatively common in our environment and is associated with adverse fetomaternal outcome when compared to the underweight subjects. There is a need for preconception care and further research to identify and possibly mitigate the risk factors of obesity.