Factors Affecting Onset of Lactogenesis II Within an Ongoing, Prospective Cohort

Background: Delayed or failed achievement of lactogenesis II (DLII)—the onset of copious milk volume—contributes to early cessation of any and/or exclusive breastfeeding.

Methods: 32 women from an ongoing, prospective cohort in Utah gave birth during 2012-2013 and completed a survey three weeks following delivery. Multivariate logistic regression models were used to estimate associations of DLII with pregnancy, delivery, and postnatal characteristics.

Results: Eight (25%) women reported DLII, defined as >3 days following delivery. Women with normal onset of lactogenesis delivered at mean 39.0 ± 1.3 gestational weeks compared to women with DLII delivering at 37.7 ± 2.5 gestational weeks (p=0.06). Women who had a C-section (n=4, 12.5%) had a 3.02 increased odds of DLII (95% CI 0.30, 30.37) compared to vaginal deliveries. Among vaginal deliveries, the odds of DLII increased by 3.64 (95% CI 0.325, 40.64) for inductions compared to spontaneous labor. For every Baby-Friendly Hospital Initiative (BFHI) practice reported, the odds of DLII decreased by 0.35 (95% CI 0.11, 1.10).

Conclusion: Preliminary findings from this ongoing, prospective cohort are consistent with previous research. DLII is more likely among women with induced labor, Caesarean delivery, and fewer BFHI practices. Future work will evaluate the association between environmental exposures to endocrine disruptors and DLII. Policies and interventions should aim to support initiation and exclusive breastfeeding by mitigating these risk factors.