Background: Little is known about how in-hospital supplementation with water, infant formula, or sugar water affects the relationship between breastfeeding intentions and duration, and whether this differs by gestational diabetes mellitus (GDM) history. Our study objectives were to assess the associations between GDM and exclusive breastfeeding intentions, hospital supplementation, and breastfeeding duration, including whether hospital supplementation mediates the association between exclusive breastfeeding intentions and breastfeeding duration.

Study design and methods: Using data from the Infant Feeding Practices Study II (2005-2007), we included women with GDM (n = 160) and women without GDM or prepregnancy diabetes (no diabetes mellitus [NDM]) (n = 2,139). We used multivariable logistic and linear regressions to determine the associations between GDM history and exclusive breastfeeding intentions, and between breastfeeding intentions, hospital supplementation, and breastfeeding duration, by GDM. We used mediation analysis to assess whether hospital supplementation mediated the association between exclusive breastfeeding intention and breastfeeding duration, also by GDM. All analyses were adjusted for prepregnancy body mass index.

Results: GDM was associated with lower odds of intending to exclusively breastfeed (adjusted odds ratio [AOR] 0.71; 95% confidence interval [CI, 0.51-0.99]). GDM and NDM women who did not intend to exclusively breastfeed had similarly increased odds of hospital supplementation (GDM: AOR 3.52; 95% CI [1.44-8.57], NDM: AOR 3.66; 95% CI [2.93-4.56]). Breastfeeding duration was similar by exclusive breastfeeding intentions and by hospital supplementation, regardless of GDM. Hospital supplementation partially mediated the association between breastfeeding intentions and duration in NDM women, but it did not mediate the association in women with GDM.

Conclusions: Breastfeeding intentions, rather than hospital supplementation, are particularly important for women with GDM to optimize breastfeeding outcomes.