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June 22, 2023

Brigham Researchers Identify Factors Associated with Lower Breastfeeding Duration for Mothers with Higher BMIs

A multi-nation cohort analysis found that inflammation and cesarean section delivery in mothers with higher body mass index are connected to shorter duration of breastfeeding, providing potential targets for intervention.

Breastfeeding has significant benefits for both maternal and child health. Research has indicated that women with higher body mass index (BMI) have shorter durations of breastfeeding, but few underlying mechanisms have been identified. To address this gap, a new study led by investigators from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, and collaborators from Boston Children’s Hospital, Icahn School of Medicine at Mount Sinai, and elsewhere, investigated the factors that may link higher maternal BMI with shorter breastfeeding duration. Their results, which are published in The American Journal of Clinical Nutrition, suggest potential strategies to help people who may be at risk for breastfeeding difficulties.

“Our study identifies modifiable factors that are associated with longer duration of lactation in people with high BMI, including dietary and systemic inflammation,” said senior author Sarbattama (Rimi) Sen, MD, a neonatologist in the Department of Pediatrics at Brigham and Women’s Hospital. “By exploring factors that could be connecting higher maternal BMI to lower breastfeeding outcomes, we are paving the way for clinical trials to test evidence-informed approaches to support breastfeeding.”

Breastfeeding has been shown to provide health benefits for both the mother and the child, including improving maternal metabolic health, decreasing rates of maternal malignancies, decreasing childhood obesity risk, and supporting child neurodevelopment. Understanding the links between maternal BMI and breastfeeding could identify new strategies for helping individuals reach their lactation goals.

The researchers analyzed data, including maternal and infant characteristics, dietary patterns and an inflammatory biomarker, collected from over 5,000 women from three different international cohorts from Spain, Greece, and the United States, supporting generalizability of the findings given cultural patterning of diet and breastfeeding.

The team reported that higher pre-pregnancy maternal BMI was indeed associated with lower breastfeeding duration across all three cohorts. They also identified three factors that partly explain this association: maternal inflammatory marker C-reactive protein, maternal dietary inflammation, and cesarean delivery. Gestational diabetes mellitus (GDM) was not found to be a significant explanatory factor underlying this association, which was surprising to study authors, but could be explained by the relatively small number of birthing parents with GDM in these cohorts.

The study provides insights into several potential targets for improving breastfeeding duration among people with overweight and obesity that can now be tested in clinical trials. These targets include reducing dietary and systemic inflammation. The findings may also inform clinical trials and providers who are caring for patients who have recently given birth.

“Breastfeeding has dose-dependent lifelong benefits for both parent and child,” said Sen. “Research such as this helps identify pathways for interventions that can support population health outcomes and equity.”

Disclosures: The authors report no conflicts of interest.

This study was supported by T32 grant HD 098061 (MK) and P30ES023515 (DV, VM). The Project Viva cohort was funded by R01 HD 034568 (EO) and UH3 OD 023286 (EO). The INfancia y Medio Ambiente (INMA) cohort was funded by Grants from Instituto de Salud Carlos III and Spanish Ministry of Health (Red INMAG03/176; CB06/02/0041; FIS 97/0588; 00/0021-2, PI061756;PS0901958; FIS-FEDER 03/1615, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/1213, 07/0314 and 09/02647; FIS-PI041436, FISPI081151, FIS-PI06/0867, FIS-PS09/00090, and CPII18/00018), Conselleria de Sanitat Generalitat Valenciana, Generalitat de Catalunya-CIRIT 1999SGR 00241, Department of Health of the Basque Government (2005111093 and 2009111069), the Provincial Government of Gipuzkoa (DFG06/004 and DFG08/001), and Fundacion Roger Torne. ISGlobal acknowledges support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. The “Rhea” project was financially supported by European projects (EU FP6-2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7ENV.2007. Project No 211250 Escape, EU FP7-2008-ENV1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009-single-stage CHICOS, EU FP7 ENV.2008. Proposal No. 226285 ENRIECO, EU-FP7-HEALTH-2012 Proposal No. 308333 HELIX) and the Greek Ministry of Health (Program of Prevention of Obesity and Neurodevelopmental Disorders in Preschool Children, in Heraklion District, Crete, Greece: 2011–2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–2015). The Rhea study was also funded by Karolinska Institutet and the Swedish Research Council (Project No. 2015-03655). Additional funding from the National Institute of Environmental Health Science (NIEHS) supported LD (R01-ES029944, R01-ES030691, R01-ES030364, R21-ES028903, R21-ES029681, and P30-ES007048).

Paper Cited: Keyes, M et al. “Mediators of the association between maternal body mass index and breastfeeding duration in 3 international cohorts”. The American Journal of Clinical Nutrition. Journal DOI: 10.1016/j.ajcnut.2023.04.004.