Height and body mass index: Who is at risk for cesarean delivery?

Article Outline

• Objective
• Study design
• Results
• Conclusion
• Copyright

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Objective 

To examine the risk of cesarean delivery in association with increasing height and body mass index.

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Study design 

This is a retrospective cohort study of nulliparous women who had a trial of labor. Maternal height was divided by 2-inch increments into 7 subgroups: <58, 58-60, 60-62 62-64 64-66, 66-68 and >68 inches. Maternal pre-pregnancy body mass index (BMI) was divided into 5 subgroups: <20, 20-24, 24-28, 28-32, and >32kg/m². The rate of cesarean delivery was examined and compared using chi-square test, and p<0.05 was used to indicate statistical significance.

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Results 

The rate of cesarean delivery was inversely associated with maternal height for each pre-pregnancy BMI category (Table). In women with a BMI<20kg/m², the risk of cesarean decreased with increasing height (p<0.001). Similarly, in women with a BMI between 20-32kg/m², the risk of cesarean decreased with increasing maternal height (p<0.001). However, above a BMI of 32 kg/m², the difference was not statistically significant.

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Conclusion 

Although body mass index is calculated from both weight and height, maternal height in combination with body mass index modifies the risk of cesarean delivery. This information may be useful in counseling women of various statures and body types.

Table: Cesarean Delivery by Height and BMI