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

ABSTRACT

OBJECTIVE: To 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. DESIGN: Retrospective cohort study using an unselected population database. SETTING: Obstetric units in Scotland, 2003-2010. POPULATION A total of 124,280 singleton deliveries in 109,592 women with a maternal BMI recorded prior to 16 weeks of gestation. METHODS: Population-based retrospective cohort study of singleton deliveries, with multivariable analysis used to assess short-term morbidity and health service costs. MAIN OUTCOME MEASURES: Maternal and offspring outcomes, number and duration of hospital admissions, and healthcare costs. RESULTS: Using 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), £59.89 (£41.61-78.17), £202.46 (£178.61-226.31), and £350.75 (£284.82-416.69), respectively. CONCLUSIONS: Maternal BMI influences maternal and neonatal morbidity, the number and duration of maternal and neonatal admissions, and health service costs.