Caesarean risk in obese women at term: A retrospective cohort analysis.

BACKGROUND: Obesity in pregnancy is a growing health problem conferring higher risk to both the woman and her infant. Internationally, peak bodies offer little guidance regarding the method and timing of delivery in these patients. Our hypothesis is that induction of labour (IOL) at term will not increase the caesarean section (CS) rate when compared to expectant management.

AIMS: To compare perinatal outcomes between IOL and expectant management in obese women at term.

METHODS: A retrospective cohort study of all term, singleton, vertex deliveries at the Townsville Hospital and Health Service from January 2011 to June 2015 in women with a body mass index (BMI) ≥ 35. Women undergoing IOL at 37 weeks were compared with women expectantly managed at that gestational age. Similar comparisons were made at 38, 39 and 40 weeks. χ2 tests and binary logistic regression were used for statistical comparison. The primary outcome measure was mode of delivery, with secondary measures of perinatal morbidity also considered.

RESULTS: There was no difference in outcome of CS, or other maternal secondary outcomes. There was no difference in rates of neonatal nursery admission. Expectant management at 38 weeks was associated with lower odds of post-partum haemorrhage (odds ratio 0.371; 95% confidence interval 0.163-0.845).

CONCLUSIONS: In women with a BMI ≥ 35, IOL does not affect the CS rate, or the risk of neonatal adverse events, but may increase the rate of postpartum haemorrhage when compared with expectant management.