Meeting paper
SMFM paper
The maternal body mass index: a strong association with delivery route

Presented in part as a poster at the 30th Annual Meeting of the Society for Maternal-Fetal Medicine, Chicago, IL, Feb. 1-6, 2010.
https://doi.org/10.1016/j.ajog.2010.06.024Get rights and content

Objective

We sought to assess body mass index (BMI) effect on cesarean risk during labor.

Study Design

The Consortium on Safe Labor collected electronic data from 228,668 deliveries. Women with singletons ≥37 weeks and known BMI at labor admission were analyzed in this cohort study. Regression analysis generated relative risks for cesarean stratifying for parity and prior cesarean while controlling for covariates.

Results

Of the 124,389 women, 14.0% had cesareans. Cesareans increased with increasing BMI for nulliparas and multiparas with and without a prior cesarean. Repeat cesareans were performed in >50% of laboring women with a BMI >40 kg/m2. The risk for cesarean increased as BMI increased for all subgroups, P < .001. The risk for cesarean increased by 5%, 2%, and 5% for nulliparas and multiparas with and without a prior cesarean, respectively, for each 1-kg/m2 increase in BMI.

Conclusion

Admission BMI is significantly associated with delivery route in term laboring women. Parity and prior cesarean are other important predictors.

Section snippets

Materials and Methods

This is an analysis of data from the Consortium on Safe Labor. The primary goal of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)-sponsored Consortium on Safe Labor was to establish a comprehensive database from multiple sites and to characterize labor and delivery in a contemporary group of women experiencing current obstetrical clinical practices. The complete database contained 228,668 deliveries from 2002 through 2008 acquired from electronic

Results

The entire Consortium on Safe Labor database consisted of 228,668 deliveries. After exclusions (18% prelabor cesareans, 4% multiple gestations, 14% deliveries <37 weeks, 21% missing BMI data, or a combination of these factors), 132,165 met the eligibility criteria for the current study. After removing 7776 deliveries of multiple pregnancies from the same mother and retaining the first delivery, 124,389 patients remained in the analysis data set, of which 17,434 (14.0%) had a cesarean delivery

Comment

Increasing BMI is associated with an increased risk of perinatal complications, including cesarean delivery. As demonstrated in this multicenter study of electronic obstetrical databases, cesarean deliveries were more likely to occur in laboring patients with greater BMIs at labor admission. In addition, these findings were consistent across strata based on parity and prior cesarean status, although the magnitude of the effects differed among the subgroups. The relative effect was most

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    This study was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, through Contract No. HHSN267200603425C.

    Reprints not available from the authors.

    Cite this article as: Kominiarek MA, VanVeldhuisen P, Hibbard J, et al. The maternal body mass index: a strong association with delivery route. Am J Obstet Gynecol 2010;203:264.e1-7.

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