Early Breastfeeding May Reduce Baby’s Risk of Childhood Obesity

For mothers who are breastfeeding, new research suggests consistent breastfeeding during the first 3 months can lower the child’s risk of childhood obesity, regardless of the mother's body mass index (BMI) before pregnancy.

The study was published in Pediatrics and funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health.

Researchers analyzed 8134 mother-child dyads from 21 cohorts within the ECHO Program, with all dyads having available data on maternal pre-pregnancy BMI, infant feeding practices, and at least 1 child BMI assessment between the ages of 2 and 6 years. The researchers utilized multivariable linear mixed models to examine the associations between breastfeeding practices and the continuous BMI for age z-score (BMIz) of the children.

The cohort of mother was mostly White (58.4%), with 17.7% of mothers being Black, and 7.7% being Asian; 21.4% of mothers were Hispanic, and 5.6% of mothers identified as multiple races. Based on BMI before the index pregnancy, 2.5% of mothers were classified as underweight (BMI <18.5 kg/m²), 45.8% as having a healthy weight (18.5 ≤ BMI <25 kg/m²), 26.0% as overweight (25 ≤ BMI <30 kg/m²), and 25.6% as having obesity (BMI ≥ 30 kg/m²).

Across the underweight, healthy weight, overweight, and obese BMI categories, the median child ages at breastfeeding cessation were 19, 26, 24, and 17 weeks for any breastfeeding, and 12, 20, 17, and 12 weeks for exclusive breastfeeding, respectively. The median (IQR) age at the time of children's BMI measurement was 3.26 years (2.48-4.57), with a total of 12,997 BMI measurements available for the longitudinal analysis, averaging 1.6 BMI measurements per child.

Woman breastfeeding | Image credit: bernardbodo – stock.adobe.com

“Exclusive breastfeeding is recommended for 6 months, in part because breastfeeding is widely acknowledged to protect against obesity and many chronic conditions over the life course,” the study authors said. “Nonetheless, women with obesity are less likely to initiate breastfeeding and are more prone to early cessation compared with women of a healthy weight, making it difficult to assess the associations between breastfeeding behavior and childhood obesity in this group. Moreover, some reports imply a deficiency in milk quality of obese women, potentially influencing their motivation and support to breastfeed.”

According to the study, children who were ever breastfed exhibited lower BMIz scores compared with children who were never breastfed, although these associations did not reach statistical significance. Notably, exclusive breastfeeding at 3 months was linked to a lower child BMIz score, but this association was only significant in women with a healthy pre-pregnancy BMI.

Specifically, compared with never breastfeeding, 3 months of any breastfeeding was associated with a lower BMIz among children whose mothers were classified as:

• Healthy weight (0.02; 0.04-0.001; P = .06)
• Overweight (0.04; 0.07-0.004; P = .03)
• Having obesity (0.04; 0.07-0.006; P = .02)

Additionally, 3 months of exclusive breastfeeding was linked to a lower BMIz among children whose mothers were classified as:

• Healthy weight (0.06; 0.10- 0.02; P = .002)
• Overweight (0.05; 0.10- 0.005; P = .07)
• Having obesity (0.08; 0.12-0.03; P = .001)

It is important to note that the researchers did not account for other exposures children could experience in their early lives that are correlated with childhood obesity risk, such as dietary patterns, physical activity, and chemical exposures.

“Based on the associations identified here, future studies and public health prevention efforts should continue focusing on addressing 2 highly prevalent problems that disproportionately affect marginalized populations resulting in adverse health outcomes: shortened duration of breastfeeding and maternal overweight and obesity,” the authors concluded. “These results support the encouragement of all women, including women who are overweight or obese before conception, to breastfeed as a preventive measure against the development of childhood obesity.”

Reference

Shipp GM, Wosu AC, Knapp EA, et al. Maternal pre-pregnancy BMI, breastfeeding, and child BMI. Pediatrics. 2024;153(1):e2023061466. doi:10.1542/peds.2023-061466