Early Postpartum Patterns of Breastfeeding Exclusivity and Perceived Insufficient Milk by Prepregnancy Body Mass...

To explore trajectories of breastfeeding exclusivity and perceived insufficient milk (PIM) over the first 8 weeks postpartum among primiparous women and the association of these trajectories with prepregnancy body mass index (BMI).

Secondary analysis of data from a randomized controlled trial.

Recruitment for the primary study was conducted in Pittsburgh, Pennsylvania.

One hundred twenty-two primiparous women with intention to exclusively breastfeed.

We used group-based trajectory modeling to classify participants into breastfeeding exclusivity and PIM trajectory groups. We used logistic regression to explore the predictive relationship between prepregnancy BMI and breastfeeding exclusivity and PIM trajectory group memberships.

We identified two trajectories each for breastfeeding exclusivity and PIM over the first 8 weeks postpartum. For breastfeeding exclusivity, one group (n = 60, 49%) had low initial probability of exclusive breastfeeding with linear decline in likelihood of exclusivity over time. The other group (n = 62, 51%) had greater initial probability of exclusive breastfeeding, which remained constant over time. For PIM, one group (n = 41, 34%) had consistently greater probability of endorsing PIM at each time point, whereas the other group (n = 81, 66%) had consistently low probability of endorsing PIM over time. Prepregnancy BMI did not predict group membership in breastfeeding exclusivity, χ²(1) = 2.8, p = .094, or PIM, χ²(1) = 0.72, p = .397.

Breastfeeding exclusivity and PIM appeared to be relatively stable phenomena in the postpartum period among a sample of predominately White primiparous women who intended to breastfeed. We did not find a clear association with prepregnancy BMI.