A new study has found, contrary to common wisdom, that alcohol does not appear to boost the mother's production of breastmilk, and actually has a counterproductive effect.
The findings provide more evidence to dispute the claim that breastfeeding women should have one or two drinks before nursing to optimize the milk supply and show no scientific evidence to support this belief.
Dr. Julie A. Mennella and colleagues at the Monell Chemical Senses Centre in Philadelphia, Pennsylvania, looked at the effect of alcohol drinking on the hormonal response of 17 healthy, non-smoking women with infants between the ages of 2 and 4 months.
Previous research indicated that breastfeeding mothers who consume moderate amounts of alcohol perceive their breasts to be fuller afterwards, but research conducted within the past 10 years suggests that alcohol is not the breastmilk-optimizing substance that many have claimed it to be.
Some cultures believe that the quality and quantity of breastmilk can be affected by a mother's psychological well-being and diet often including the consumption of beer, wine and fermented fruit juices.
The benefits of drinking before breastfeeding, it has been claimed by midwives and other healthcare professionals, will make infants relax as well as boost the mother's production of milk.
In this study, drinking alcohol before breastfeeding diminished the mother's production of breastmilk.
After drinking orange juice containing the alcohol equivalent to one or two glasses of wine, the women used electric breast pumps to stimulate their production of breast milk. The researchers recorded the amount of time it took for the first droplet of milk to be produced as well as the total amount of milk pumped during a 16-minute period.
Levels of prolactin and oxytocin, hormones crucial to the production and flow of breast milk, normally rise when babies are at the breast or when mothers use breastpumps and the researchers found that when the mothers consumed alcohol their oxytocin levels dropped by 78 percent and levels of prolactin increased more than three-fold. These hormones, which usually work in tandem, "go in separate directions" after women have one or two drinks.
The women produced less milk overall, and their breastmilk took longer to flow. Mennella says mothers may be more relaxed after a drink or two but unbeknownst to them, the hormones that underlie lactation will be disrupted, and rather than boosting their milk supply, these mothers may produce less milk, and their babies possibly drink less milk in the short term.
Mennella adds that alcohol is not stored in the breasts, so if a mother has a glass of wine, she can safely breastfeed two or three hours later without worrying that her infant will consume alcohol-tainted milk.
The researchers concluded that "the long-term consequences of such disruptions on lactational performance and women's health, in general, remains unknown."
The report can be found in the Journal of Clinical Endocrinology & Metabolism.