Objectives The literature contains little information on the economic effect of obesity on maternity services. We aimed to assess the cost impact of obesity on antenatal, intrapartum and postpartum care.

Methods Retrospective cohort study. Study group: BMI > 30 (n = 72). Control group: BMI 18.5 – 25 (n = 68). Exclusion criteria: breech, pre-existing hypertension/diabetes, multiple pregnancy, late bookers. Costing information from NI Database of Healthcare Resource Group Costs. Outcomes recorded and statistical analysis performed.

Results Overall cost of maternity care in the obese group (£11699) was significantly higher than the normal BMI group (£10643) (p = 0.026, power 73%). Further analysis revealed the greatest cost difference was with antenatal care (p = 0.005, power 89%) from increased appointments and admissions due to increased rates of PIH, PET and GDM. There was no significant difference in the cost of intrapartum care (Normal BMI £2424, Obese £2355, p = 0.669) or postpartum care (Normal BMI £1097, Obese £1052, p = 0.627). The obese group had a higher rate of NVD (61% versus 47%), and Caesarean delivery (18% versus 13%) and lower rate of instrumental delivery (21% versus 40%). The incidences of PPH were similar, with a higher rate of 3rd degree tears in the normal BMI group. Birth-weights and SCBU admissions were similar with a higher rate of breastfeeding in the normal BMI group (60% versus 53%).

Conclusion Obesity significantly increases the cost of maternity care by over £1000 per patient. This study highlights the importance of investment in maternity services and weight management programmes to cope with the evolving obesity epidemic.