This retrospective analysis evaluated the association between maternal body mass index (BMI) and the incidence of maternal and neonatal complications in those women delivering at a North West London hospital between January 2002 and December 2007. Of the women examined, obese mothers (BMI ≥ 30) were shown to be at significantly higher risk from multiple morbidities (p < 0.05), including gestational diabetes; antepartum haemorrhages; pre-term delivery before 37 and 33 weeks' gestation; induction of labour; analgesia use (beyond inhalational methods and local infiltration); caesarean sections; massive postpartum haemorrhages; higher birth weights; Apgar scores < 8 at 1 min and 5 min; cord base deficits less than-12 and a greater need for neonatal care (SCBU, HDU, NICU) compared with mothers with a BMI < 30. These findings add to the growing consensus that obesity increases the risks involved with pregnancy. While information is filtering through to the general public about the overall risks of obesity, more focused pre-pregnancy and inter-pregnancy counselling on the implications of a raised BMI specifically on pregnancy is required at both primary and secondary care sector levels.