Breastfeeding behaviours in women with obesity; associations with weight retention and the serum metabolome: a secondary analysis of UPBEAT.

Background/objectives: Maternal obesity is associated with a decreased intention and initiation of breastfeeding as well as a shortened duration of breastfeeding. This analysis was undertaken to identify breastfeeding behaviours, and relationships with maternal anthropometry and the serum metabolome at 6-months postpartum in an ethnically diverse cohort of women with obesity.

Subjects/methods: A cohort analysis of 715 women from the UK Pregnancies Better Eating and Activity Trial (UPBEAT); a multi-centre randomised controlled trial of an antenatal lifestyle intervention in women with obesity. Maternal data were collected in early pregnancy and included body mass index (BMI), socio-demographic characteristics and anthropometry. At 6-months postpartum, breastfeeding behaviours, anthropometry and 158 maternal metabolic measures from blood samples were recorded. Kaplan-Meier curves of breastfeeding duration were constructed and were stratified by obesity class (I: BMI 30.0-34.9 kg/m, II: 35.0-39.9 kg/m, III: ≥40.0 kg/m). Relationships between breastfeeding behaviours, socio-demographic characteristics, the metabolome, and anthropometry were determined using regression analyses.

Results: Eighty-two percent (591/715) of the cohort-initiated breastfeeding and at the 6-month follow-up 40% (283/715) were breastfeeding exclusively or partially. Duration of exclusive breastfeeding decreased with increasing BMI: Compared to BMI class I (mean 90.4 ± 64 days) the difference in mean for classes II and III were -15.8 days (95% confidence interval: -28.5, -3.1, p < 0.05) and -16.7 (95% CI: -32.0 to -1.35, p < 0.05), respectively. Compared to no breastfeeding, any breastfeeding at 6-months postpartum was associated with improvements in metabolites towards a healthier profile, reduced weight retention by -1.81 kg (95% CI -0.75, -2.88, p < 0.05 ) and reduced anthropometric measures, including mid-upper arm and hip circumferences. The breastfeeding related changes in anthropometry were not evident in women of Black ethnicity.

Conclusions: Greater emphasis on enabling breastfeeding for women with obesity could improve duration, women's weight management and metabolic health. The lack of breastfeeding related anthropometric effects in Black women requires further investigation.

Clinical Trial Registry: ISRCTN reference 89971375.