Counseling for Fetal Macrosomia: An Estimated Fetal Weight of 4,000 g is Excessively Low

Abstract

Objective Because of the known complications of fetal macrosomia, our hospital's policy has been to discuss the risks of shoulder dystocia and cesarean section (CS) in mothers with a sonographic estimated fetal weight (SEFW) ≥ 4,000 g at term. The present study was performed to determine the effect of this policy on CS rates and pregnancy outcome.

Study Design We examined the pregnancy outcomes of the macrosomic (≥ 4,000 g) neonates in two cohorts of nondiabetic low risk women at term without preexisting indications for cesarean: (1) SEFW ≥ 4,000 g (correctly suspected macrosomia) and (2) SEFW < 4,000 g (unsuspected macrosomia).

Results There were 238 neonates in the correctly suspected group and 205 neonates in the unsuspected macrosomia group, respectively. Vaginal delivery was accomplished in 52.1% of the suspected group and 90.7% of the unsuspected group, respectively, p < 0.001. There was no difference in the rates of shoulder dystocia. The odds ratio for CS was 9.0 (95% confidence interval, 5.3–15.4) when macrosomia was correctly suspected.

Conclusion The policy of discussing the risk of macrosomia with SEFW ≥ 4,000 g to women is not justified. A higher SEFW to trigger counseling for shoulder dystocia and CS, more consistent with American College of Obstetrics and Gynecology (ACOG) guidelines, should be considered.

Keywords

macrosomia - estimated fetal weight - cesarean section - shoulder dystocia - counseling

Note

An abstract of the data presented in this article has been accepted for poster presentation at the Society of Maternal-Fetal Medicine Annual Meeting in February 2014.

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