Determinants of lactation performance across time in an urban population from Mexico.

We identified determinants of breastfeeding and full breastfeeding among 165 healthy mothers from Hermosillo, Mexico who planned to breastfeed and delivered vaginally a healthy term infant. Deliveries took place in either a nursery (n = 58) or a rooming-in (n = 107) public hospital where formula supplementation was not allowed. Multivariate analyses indicated that at 1 week full breastfeeding was associated (P < or = 0.05) with early milk arrival, social support for full breastfeeding and planned breastfeeding duration. At 2 months, full breastfeeding was associated with social support for full breastfeeding and early milk arrival. Breastfeeding was positively associated with early milk arrival and inversely associated with early introduction of supplementary bottles, maternal employment, maternal body mass index and infant age. At 4 months, full breastfeeding was positively associated with social support for full breastfeeding and inversely associated with infant age. Breastfeeding was positively associated with planned breastfeeding duration and inversely associated with early introduction of a bottle and urban background. Rooming-in mothers reported that their milk came in earlier (P < or = 0.05) than did the nursery group. Milk arrival was later when a bottle was introduced in the first week; both of these variables might be important in explaining a positive effect of rooming-in on lactation performance.