In moderation of course, not if you co-sleep and not whilst driving!

All this is fromThe La Leche League International at  http://www.llli.org/FAQ/alcohol.html where you can find full links to the research.

“What about drinking alcohol and breastfeeding?

Women are often warned to not consume alcohol during pregnancy, as ample evidence has shown that it poses a severe and avoidable risk to her unborn baby. The risks of consuming alcohol while breastfeeding are not as well defined. Breastfeeding mothers receive conflicting advice about whether alcohol consumption can have an effect on their baby, which often leaves mothers feeling like they have more questions than answers. So, what information should a mother who is considering drinking while breastfeeding know?

La Leche League’s The Womanly Art Of Breastfeeding (p. 328) says:
The effects of alcohol on the breastfeeding baby are directly related to the amount the mother ingests. When the breastfeeding mother drinks occasionally or limits her consumption to one drink or less per day, the amount of alcohol her baby receives has not been proven to be harmful.

La Leche League’s The Breastfeeding Answer Book (pp. 597-598) says:
Alcohol passes freely into mother’s milk and has been found to peak about 30 to 60 minutes after consumption, 60 to 90 minutes when taken with food. Alcohol also freely passes out of a mother’s milk and her system. It takes a 120 pound woman about two to three hours to eliminate from her body the alcohol in one serving of beer or wine…the more alcohol that is consumed, the longer it takes for it to be eliminated. It takes up to 13 hours for a 120 pound woman to eliminate the alcohol from one high-alcohol drink. The effects of alcohol on the breastfeeding baby are directly related to the amount the mother consumes.

The American Academy of Pediatrics Committee on Drugs considers alcohol compatible with breastfeeding. It lists possible side effects if consumed in large amounts, including: drowsiness, deep sleep, weakness, and abnormal weight gain in the infant, and the possiblity of decreased milk-ejection reflex in the mother. The drug transfer table is available at http://aappolicy.aappublications.org/cgi/content/full/pediatrics;108/3/776/T6 and the full text of The Transfer of Drugs and Other Chemicals Into Human Milk can be found at http://aappolicy.aappublications.org/cgi/content/full/pediatrics;108/3/776

Dr. Jack Newman, member of the LLLI Health Advisory Council, says this in his handout “More Breastfeeding Myths”:
Reasonable alcohol intake should not be discouraged at all. As is the case with most drugs, very little alcohol comes out in the milk. The mother can take some alcohol and continue breastfeeding as she normally does. Prohibiting alcohol is another way we make life unnecessarily restrictive for nursing mothers.

Thomas W. Hale, R.Ph. Ph.D., member of the LLLI Health Advisory Council, says this in his book Medications and Mothers’ Milk (12th ed.):
Significant amounts of alcohol are secreted into breastmilk although it is not considered harmful to the infant if the amount and duration are limited. The absolute amount of alcohol transferred into milk is generally low. Beer, but not ethanol, has been reported in a number of studies to stimulate prolactin levels and breastmilk production (1, 2, 3). Thus it is presumed that the polysaccharide from barley may be the prolactin-stimulating component of beer (4). Non-alcoholic beer is equally effective.

In a study of twelve breastfeeding mothers who ingested 0.3 g/kg of ethanol in orange juice (equivalent to 1 can of beer for the average-sized woman), the mean maximum concentration of ethanol in milk was 320 mg/L (5). This report suggests a 23% reduction (156 to 120 mL) in breastmilk production following ingestion of beer and an increase in milk odor as a function of ethanol content.

Excess levels may lead to drowsiness, deep sleep, weakness, and decreased linear growth in the infant. Maternal blood alcohol levels must attain 300 mg/dl before significant side effects are reported in the infant. Reduction of letdown is apparently dose-dependent and requires alcohol consumption of 1.5 to 1.9 gm/kg body weight (6). Other studies have suggested psychomotor delay in infants of moderate drinkers (2+ drinks daily). Avoid breastfeeding during and for 2 – 3 hours after drinking alcohol.

In an interesting study of the effect of alcohol on milk ingestion by infants, the rate of milk consumption by infants during the 4 hours immediately after exposure to alcohol (0.3 g/kg) in 12 mothers was significantly less (7). Compensatory increases in intake were then observed during the 8 – 16 hours after exposure when mothers refrained from drinking.

Adult metabolism of alcohol is approximately 1 ounce in 3 hours, so mothers who ingest alcohol in moderate amounts can generally return to breastfeeding as soon as they feel neurologically normal. Chronic or heavy consumers of alcohol should not breastfeed.

References:

1. Marks V, Wright JW. Endocrinological and metabolic effects of alcohol. Proc R Soc Med 1977; 70(5):337-344.

2. De Rosa G, Corsello SM, Rufilli MP, Della CS, Pasargiklian E. Prolactin secretion after beer. Lancet 1982; 2(8252):934.

3. Carolson HE, Wasser HL, Reidelberger RD. Beer-induced prolactin secretion: a clinical and laboratory study of the role of salsolinol. J Clin Endocrinol Metab 1985; 60(4):673-677.

4. Koletzko B, Lehner F. Beer and breastfeeding. Adv Exp Med Biol 2000; 478:23-28.

5. Mennella JA, Beauchamp GK. The transfer of alcohol to human milk. Effects on flavor and the infant’s behavior. N Engl J Med 1991; 325(14):981-985.

6. Cobo E. Effect of different doses of ethanol on the milk-ejecting reflex in lactating women. Am J Obstet Gynecol 1973; 115(6):817-821.

7. Mennella JA. Regulation of milk intake after exposure to alcohol in mothers’ milk. Alcohol Clin Exp Res 2001; 25(4):590-593.
Important Considerations
Your baby’s age
A newborn has an immature liver, and will be more affected by alcohol
Up until around 3 months of age, infants metabolize alcohol at about half the rate of adults
An older baby can metabolize alcohol more quickly than a young infant
Your weight
A person’s size has an impact on how quickly they metabolize alcohol
A heavier person can metabolize alcohol more quickly than a lighter person
Amount of alcohol
The effect of alcohol on the baby is directly related to the amount of alcohol that is consumed
The more alcohol consumed, the longer it takes to clear the mother’s body
Will you be eating
An alcoholic drink consumed with food decreases absorbtion
Can drinking an alcoholic beverage help me relax and stimulate milk production?

Alcohol consumption has not been shown to stimulate milk production. Studies have found that babies nurse more frequently, but consume less milk in the 3-4 hours after an alcoholic beverage is consumed.
Do I have to pump and dump after drinking an alcoholic beverage?

As alcohol leaves the bloodstream, it leaves the breastmilk. Since alcohol is not “trapped” in breastmilk (it returns to the bloodstream as mother’s blood alcohol level declines), pumping and dumping will not remove it. Pumping and dumping, drinking a lot of water, resting, or drinking coffee will not speed up the rate of the elimination of alcohol from your body.
What if I get drunk?

Mothers who are intoxicated should not breastfeed until they are completely sober, at which time most of the alcohol will have left the mother’s blood. Drinking to the point of intoxication, or binge drinking, by breastfeeding mothers has not been adequately studied. Since all of the risks are not understood, drinking to the point of intoxication is not advised.
Can alcohol abuse affect a breastfed baby?

Yes. Alcohol abuse (excessive drinking) by the mother can result in slow weight gain or failure to thrive in her baby. The let-down of a mother who abuses alcohol may be affected by her alcohol consumption, and she may not breastfeed enough. The baby may sleep through breastfeedings, or may not suck effectively leading to decreased milk intake. The baby may even suffer from delayed motor development. If you are concerned that you or someone you know is drinking alcohol excessively, call your doctor.
Weighing the Risks and Benefits

Many mothers find themselves in a situation where they may want to drink. Maybe you are going to a wedding where wine will be served. Or perhaps you are going on a girls night out, or on a date with your husband. No matter the reason, you may have concerns about drinking and any possible effects on your baby. It is a good idea to weigh the benefits of breastfeeding against the benefits and possible risks of consuming alcohol. You might find the following suggestions helpful.
Plan Ahead
If you want to drink, but are concerned about the effect on your baby, you can store some expressed breastmilk for the occasion
You can choose to wait for the alcohol to clear your system before nursing
If your breasts become full while waiting for the alcohol to clear, you can hand express or pump, discarding the milk that you express
Alternatives
If consuming alcohol while breastfeeding is concerning to you, consider enjoying a non-alcoholic beverage instead. Any drink is more fun with an umbrella in it!
Additional Information

Alcohol and Motherhood, an article from LEAVEN (our journal for Leaders)
Resources

The Breastfeeding Answer Book

The Womanly Art Of Breastfeeding

The Transfer of Drugs and Other Chemicals Into Human Milk

More Breastfeeding Myths — Jack Newman, MD, FRCPC

Medications and Mothers’ Milk (12th ed.), Thomas W. Hale, R.Ph. Ph.D.

Page last edited Fri Jun 26 15:53:01 UTC 2009.