Fetal macrosomia and pregnancy outcomes

Aust N Z J Obstet Gynaecol. 2009 Oct;49(5):504-9. doi: 10.1111/j.1479-828X.2009.01052.x.


Background: Pregnancies with a macrosomic fetus comprise a subgroup of high-risk pregnancies. There is uncertainty in the clinical management and outcomes of such pregnancies.

Aim: We sought to examine clinical management and maternal and fetal outcomes in pregnancies with macrosomic infants at Royal Brisbane and Women's Hospital (RBWH).

Methods: Data from 276 macrosomic births (weighing > or = 4500 g) and 294 controls (weighing 3250-3750 g) delivered during 2002-2004 at RBWH were collected from the hospital database. Univariate and logistic regression analyses were performed for maternal risk factors and maternal and neonatal outcomes that were associated with fetal macrosomia.

Results: Macrosomia was more than two times likely in women with body mass index (BMI) of > 30 kg/m(2) (odds ratio (OR) 2.41, 95% confidence interval (CI) 1.26-4.61) and in male infant sex (OR 2.05, 95% CI 1.35-3.12), and four times more likely in gestation of > 40 weeks (OR 3.93, 95% CI 1.99-7.74). Maternal smoking reduced the risk of fetal macrosomia (OR 0.27, 95% CI 0.14-0.51). Macrosomia was associated with nearly two times higher risk of emergency caesarean section (OR 1.75, 95% CI 1.02-2.97) and maternal hospital stay of > 3 days (OR 1.66, 95% CI 1.11-2.50), and four times higher risk of shoulder dystocia (OR 4.08, 95% CI 1.62-10.29). Macrosomic infants were twice as likely to have resuscitation (OR 2.21, 95% CI 1.46-3.34) and intensive care nursery admission (OR 1.89, 95% CI 1.03-3.46).

Conclusion: Macrosomia was associated with an increased risk of adverse maternal and neonatal health outcomes. Optimal management strategies of macrosomic pregnancies need evaluation.

MeSH terms

  • Adult
  • Birth Injuries / etiology
  • Body Mass Index
  • Cesarean Section
  • Dystocia / etiology
  • Female
  • Fetal Macrosomia*
  • Humans
  • Infant, Newborn
  • Intensive Care Units, Neonatal
  • Length of Stay
  • Male
  • Odds Ratio
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy, High-Risk*
  • Retrospective Studies
  • Sex Distribution
  • Young Adult