Non-diabetic fetal macrosomia: outcomes of elective delivery versus expectant management.

Background: Macrosomia in the absence of diabetes can be associated with increased neonatal and maternal morbidity. Management is usually undertaken on a case-by-case basis.

Aims: In order to inform local practice, this study aimed to evaluate the outcomes of the management of non-diabetic macrosomia in an Irish tertiary center.

Methods: A retrospective observational study was performed on all women with estimated fetal weight over 4000 g after 37 weeks' gestation. Maternal demographics and obstetric and neonatal outcomes were recorded using the hospital information system. Women with diabetes, previous caesarean section, non-cephalic presentation, or any other complicating condition were excluded. Women were divided into two groups: 1. Active management: Elective delivery for macrosomia-between 38 + 0 and 40 + 6 weeks' gestation 2. Expectant management: with induction of labour offered after 41 weeks' gestation RESULTS: There were 397 women included, 188 with active and 209 with expectant management. There was no difference in adverse neonatal outcomes, major maternal morbidity, or mode of delivery, after exclusion of pre-labor caesarean section. Women with expectant management were more likely to go into spontaneous labor (46.9 vs 1.6%, p < 0.001) and to have a favorable cervix at the onset of induction of labor if nulliparous (86.1 vs 70.0%, p = 0.021), but have higher rates of episiotomy (28.6 vs 18.2%, p = 0.021). With active management, nulliparas with an unfavorable cervix had increased risk of anal sphincter injury (6.5 vs 0.0%, p = 0.007) and postpartum hemorrhage (59.0 vs 35.5%, p = 0.003).

Conclusions: Overall, there was no difference in major maternal or neonatal outcomes between management options for fetal macrosomia. However, inducing nulliparas with an unfavorable cervix for non-diabetic macrosomia was associated with obstetric anal sphincter injury and postpartum hemorrhage.