Prepregnancy obesity as a risk factor for exclusive breastfeeding initiation in Japanese women

Breastfeeding rates in many countries fall short of the World Health Organization's recommendations. It has been reported that exclusive breastfeeding (EBF) is negatively associated with obesity; however, the association varies with ethnicity, and little information is available from Asia. We explored whether prepregnancy body mass index (BMI) and gestational weight gain (GWG) were associated with initiation of EBF.

We investigated 6125 Japanese women with full-term (37-42 wk of gestation) singleton babies between January 2010 and June 2013, in a hospital with the largest annual number of deliveries in Tokyo, Japan.

Successful EBF initiation was observed in 72% of women 1 mo after delivery. The average GWG was 10 kg in underweight (BMI < 18.5 kg/m²) and normal weight (BMI 18.5-24.9 kg/m²) women; 7 kg in overweight (BMI 25-29.9 kg/m²) women, and 4 kg in obese (BMI ≥ 30 kg/m²) women. After adjusting for covariates, stepwise modeling revealed that compared with women of normal weight, obesity (odds ratio [OR], 0.29; 95% confidence interval [CI], 0.16-0.53), and a single-unit increase in the GWG (OR, 0.98; 95% CI, 0.96-1.00) were significantly associated with unsuccessful EBF initiation. No statistical interaction was evident between prepregnancy BMI and GWG. Other significant risk factors for unsuccessful EBF initiation included older maternal age (P < 0.001), nulliparity (P < 0.001), cesarean delivery (P < 0.001), an earlier gestational week (P < 0.001), a light-for-date infant (P < 0.05), and mother-child separation for clinical reasons (P < 0.001).

This study suggested that prepregnancy obesity is a risk factor for EBF initiation among Japanese women.