A comparison of breastfeeding rates by obesity class

Abstract

Purpose: The purpose of this study is to compare breastfeeding initiation rates for women across body mass index (BMI) classes, including normal BMI (18.50-24.99 kg/m²), overweight (25.00-29.99 kg/m²), obese (30.00-39.99 kg/m²), morbidly obese (40.00-49.99 kg/m²) and extreme obesity (≥50.00 kg/m²).

Materials and methods: Retrospective cohort of women with singleton pregnancies, delivering in St. John's, NL between 2002 and 2011. The primary outcome was any breastfeeding on hospital discharge. Breastfeeding rates across BMI categories were compared, using univariate analyses. Multivariate analysis included additional maternal and obstetric variables.

Results: Twelve thousand four hundred twenty-two women were included: 8430 breastfed and 3992 did not breastfeed on hospital discharge. Progressively decreasing rates of breastfeeding were noted with increasing obesity class: normal BMI (71.1%), overweight (69.1%), obese (61.6%), morbidly obese (54.2%), and extremely obese women (42.3%). Multivariate analysis confirmed that increasing obesity class resulted in lower odds of breastfeeding: overweight (adjusted odds ratios (aOR) 0.86, 95%CI 0.76-0.98), obese (aOR 0.65, 95%CI 0.57-0.74), morbidly obese (aOR 0.57, 95%CI 0.44-0.74), and extreme obesity (aOR 0.37, 95%CI 0.19-0.74).

Conclusion: Women in higher obesity classes are progressively less likely to initiate breastfeeding. Women with the highest prepregnancy BMIs should be particularly counseled on the benefits of breastfeeding.

Keywords: BMI; breastfeeding; breastfeeding initiation; obesity class; pregnancy outcome.