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Cross‐national differences in early lactation success among primiparous women

We evaluated early lactation success in two cohorts of primiparas who initiated breastfeeding: 448 in Sacramento, CA and 171 in Lima, Peru. Key outcomes were sub‐optimal infant breastfeeding behavior (SIBB), onset of stage II lactogenesis >72 h postpartum (delayed OL) and excess neonatal weight loss (≥ 10% of birth weight by 70–98 h). All adverse outcomes were significantly more common in California than in Peru: 69% vs. 52% for SIBB on day 0 (p=0.0004), 34% vs. 21% for SIBB on day 3 (p=0.005), 44% vs. 17% for delayed OL (p<0.0001), and 18% vs. 10% for excess weight loss (p=0.03). For SIBB on day 0, 33% of the site difference could be explained by lower breastfeeding frequency on day 0 in California. For SIBB on day 3, 45% of the site difference could be explained by lower breastfeeding frequency on day 0 and greater prevalence of flat or inverted nipples in California. For delayed OL, 27% of the site difference could be explained by greater maternal age and BMI, greater birth weight and lower Apgar scores in California. For excess weight loss, 91% of the site difference could be explained by greater maternal age and BMI in California. We conclude that the higher prevalence of early breastfeeding problems in California is linked to maternal characteristics and lower breastfeeding frequency soon after birth. Supported by grant R40MC04294 from the Department of Health and Human Services, Maternal Child Health Branch.