Association between maternal body mass index during pregnancy, short-term morbidity, and increased health service costs: a population-based study

ObjectiveTo investigate the impact of maternal body mass index (BMI, kg/m(2)) on clinical complications, inpatient admissions, and additional short-term costs to the National Health Service (NHS) in Scotland. DesignRetrospective cohort study using an unselected population database. SettingObstetric units in Scotland, 2003-2010. PopulationA total of 124280 singleton deliveries in 109592 women with a maternal BMI recorded prior to 16weeks of gestation. MethodsPopulation-based retrospective cohort study of singleton deliveries, with multivariable analysis used to assess short-term morbidity and health service costs. Main outcome measuresMaternal and offspring outcomes, number and duration of hospital admissions, and healthcare costs. ResultsUsing multivariable analysis, in comparison with women of normal weight, women who were overweight, obese, or severely obese had an increased risk of essential hypertension [1.87 (1.18-2.96), 11.90 (7.18-19.72), and 36.10 (18.33-71.10)], pregnancy-induced hypertension [1.76 (1.60-1.95), 2.98 (2.65-3.36), and 4.48 (3.57-5.63)], gestational diabetes [3.39 (2.30-4.99), 11.90 (7.54-18.79), and 67.40 (37.84-120.03)], emergency caesarean section [1.94 (1.71-2.21), 3.40 (2.91-3.96), and 14.34 (9.38-21.94)], and elective caesarean section [2.06 (1.84-2.30), 4.61 (4.06-5.24), and 17.92 (13.20-24.34)]. Compared with women of normal weight, women who were underweight, overweight, obese, or severely obese were associated with an 8, 16, 45, and 88% increase in the number of admissions, respectively, and women who were overweight, obese, or severely obese were associated with a 4, 9, and 12% increase in the duration of stay (all P<0.001). The additional maternity costs [mean (95%CI), adjusted analyses] for women who were underweight, overweight, obese, or severely obese were 102.27 (48.49-156.06) pound, 59.89 pound (41.61-78.17) pound, 202.46 pound (178.61-226.31) pound, and 350.75 pound (284.82-416.69) pound, respectively. ConclusionsMaternal BMI influences maternal and neonatal morbidity, the number and duration of maternal and neonatal admissions, and health service costs.