• Complications;
  • obesity;
  • pregnancy

Objective  To investigate the effect of maternal body mass index (BMI) on minor complications, associated additional medication use during pregnancy and the consequent cost implications.

Design  Retrospective analysis of case notes.

Setting  Labour wards, tertiary referral hospital, Royal Infirmary Edinburgh, UK.

Population  Six hundred and fifty-one women with a singleton pregnancy over four separate time periods in 2007 and 2008.

Methods  Descriptive statistics, univariate and multivariate logistic regression analysis and cost analysis using standard techniques and inflation indices.

Main outcome measures  Minor complications, use of medications during pregnancy and consequent incremental costs from the perspective of the National Health Service (NHS).

Results  42.4% of women were overweight or obese (BMI ≥ 25 kg/m2). Higher BMI during the first trimester (BMI ≥ 30 kg/m2 compared with BMI < 25 kg/m2) was associated with an increased risk of minor complications including symphysis pubis dysfunction (OR 3.97; 95% CI 2.19–7.18), heartburn (OR 2.65; 95% CI 1.42–4.94) and chest infection (OR 8.71; 95% 2.20–34.44) and with drugs used to treat these complications including Gaviscon (OR 3.52; 95% CI 1.78–6.96). The mean incremental (additional) NHS costs per woman for treating minor complications increased with maternal BMI were £15.45/woman, £17.64/woman and £48.66/woman for BMI < 25 kg/m2, BMI ≥ 25 to <30 kg/m2 and BMI ≥ 30 kg/m2 respectively.

Conclusions  Increased maternal BMI is associated with increased risk of developing minor complications during pregnancy; use of medications associated with treating these conditions and has significant NHS costs.