Induction of Labor
The rates of induction of labor are steadily increasing in recent years. Induction of labor is performed in almost 24% of pregnancies between 37 and 41 weeks of gestation in the USA. The justification for performing an elective delivery in a patient with DM includes a potential reduction in perinatal complications, especially those related to macrosomia. In a recent review discussing the indications for induction of labor, it was shown that induction of labor in suspected fetal macrosomia (without DM) does not improve outcomes; however, the quality of evidence was moderate and the grade of recommendation against induction of labor was weak. Another conclusion of this review was that induction of labor may increase the rate of Caesarean deliveries. The level of evidence was, again, low and the grade of recommendation against induction of labor was poor.
There is only one randomized, controlled trial that addressed the issue of induction of labor in women with DM treated with insulin at term. In this study, 200 such women were allocated to receive either induction at 38 weeks of gestation or expectant care. This study found no difference in the rate of Caesarean delivery between these approaches but found that fetal macrosomia (birthweight > 4000 g) was significantly reduced by induction of labor (relative risk: 0.56; 95% CI: 0.32-0.98; number needed to treat: 8). The birthweight of 23% of the babies born to expectantly managed women was at or above the 90th percentile compared with 10% of the babies born to induced women. There were more cases of shoulder dystocia in the expectantly managed group, but this difference was not statistically significant. There were no differences in other fetal or maternal morbidities. This study had been quoted in the Cochrane and also other systematic reviews regarding this issue.[54,57]
There are four observational studies that also address this issue.[58,59,60,61] All four studies suggest a potential reduction in macrosomia and shoulder dystocia with induction of labor and Caesarean delivery for EFW indications, but there was inadequate evidence to review other clinical outcomes.
Pregestational DM differs from GDM in the risk of IUFD, which is increased in pre-GDM, particularly when it is poorly controlled; this could be the main reason for the higher risk for induction of labor of women with pre-GDM than women with GDM, aside from the fear from macrosomic babies.
In the Confidential Enquiry into Maternal and Child Health, it was found that women with pre-GDM were nearly twice as likely to be induced (38.9%) compared with the general maternity population (21%).
Expert Rev of Obstet Gynecol. 2009;4(5):547-554. © 2009 Expert Reviews Ltd.
Cite this: Managing Labor and Delivery of the Diabetic Mother - Medscape - Sep 01, 2009.