Breastfeeding and prolactin levels in lactating women with a family history of alcoholism.

Scientific evidence overwhelmingly indicates that breastfeeding confers significant health benefits to mother and child and is the ideal method for feeding and nurturing infants. The US public health goals are for at least 75% of the nation’s new mothers to breastfeed at hospital discharge and at least 50% to breastfeed throughout the first 6 months of their child’s life.1 Although a variety of social and cultural factors may influence a woman’s decision to breastfeed, even many highly motivated women fail to reach these goals.2 Consequently, there has been great interest in identifying risk factors for poor breastfeeding performance and mechanisms that can be targeted by supportive interventions. Prolactin is one of the principal lactogenic hormones, and blunted prolactin response to suckling has previously been identified as a major mechanism of breastfeeding failure during the early stages of lactation.3 Suckling, the most potent physiologic stimulus of prolactin, upregulates opioids and other factors that inhibit dopamine secretion into the portal circulation.4,5 Dopamine inhibitors, such as phenothiazines, metoclopramide, domperidone, and alcohol, also cause hyperprolactinemia, 6 and some are used specifically as galactagogues.7 Encouraging lactating women to drink alcohol as a means to increase milk production is a widespread folklore8,9 that is still perpetuated by early evidence, albeit in men and nonlactating women, that alcohol consumption can increase circulating prolactin10,11; however, the first evidence that alcohol influences lactation were reports that maternal alcohol intake decreased the milk intake of rat pups.12,13 Consistent with these animal studies, we have shown that after lactating women consume a moderate dose of alcohol, their infants breastfeed less despite sucking more intensely during the initial minutes of feeding.14,15 This is, at least in part, because moderate doses of alcohol, despite stimulating prolactin release, interfere with milk ejection in a time-dependent manner and milk production during a 4- to 5-hour period.16–18 A number of studies indicated that men and nonlactating women who had a history of alcohol dependence in first- or second-generation family members but were not themselves alcoholics were less acutely influenced by the sedative and motor effects of alcohol than are individuals without such a family history.19–21 Although alcohol consumption results in increased prolactin levels, individuals with a familial history of alcoholism exhibit a blunted prolactin response to alcohol,19,20 suggesting that family history alone may be an important indicator of prolactin dynamics; however, this research was conducted in men and nonlactating women, and, to the best of our knowledge, there have been no such studies of lactating women. This study tests the hypothesis that lactating women who have a family history of alcoholism but themselves are not alcoholics exhibit smaller prolactin responses to suckling and an alcohol challenge than do women without such a family history. We focused on women in established lactation. Although relative differences in prolactin responses to suckling in established lactation are likely to reflect hormonal responses in early lactation, 22 prolactin is not critical in established lactation as it is in early lactation. We therefore hypothesized that if family history of alcoholism has a negative impact on prolactin responses, then these women are likely to exhibit compensatory changes in breastfeeding patterning that will be evident during established lactation, and despite alcohol-induced elevations in prolactin, alcohol consumption will not enhance lactational performance.