The combined effect of maternal obesity and fetal macrosomia on pregnancy outcomes.

OBJECTIVE

To examine the combined effect of macrosomia and maternal obesity on adverse pregnancy outcomes using a retrospective cohort.

METHODS

Infants with a birth weight of ≥ 4000g (macrosomia) were identified from an institutional birth cohort. Demographic characteristics and maternal, fetal, neonatal, and pregnancy outcomes of macrosomic infants whose mothers were obese were compared with those whose mothers were non-obese.

RESULTS

Pregnancies in obese women resulting in macrosomic infants are more likely to be complicated by gestational diabetes, gestational hypertension, and smoking than pregnancies in non-obese women with macrosomic infants. Mothers whose infants are macrosomic are significantly more likely to require induction of labour (OR 1.42; 95% CI 1.10 to 1.98) and delivery by Caesarean section (OR 1.45; 95% CI 1.04 to 2.01), particularly for maternal indications (OR 3.7; 95% CI 1.47 to 9.34), if they are obese. Finally, macrosomic infants of obese mothers are significantly more likely to require neonatal resuscitation in the form of free flow oxygen (OR 1.57; 95% CI 1.03 to 2.42) than macrosomic infants of non-obese mothers.

CONCLUSION

When both maternal obesity and macrosomia are present, adverse pregnancy outcomes are more common than when fetal macrosomia occurs in a woman of normal weight.