In a nutshell: Alcohol does transfer into your breastmilk in small amounts. Studies suggest that regularly drinking heavily (more than 2 units a day) when you’re breastfeeding can affect your baby’s hormone balance, general alertness and weight gain, as well as affecting your milk supply 1. It can also, obviously, make you less capable of looking after your baby safely.
But having the occasional alcoholic drink while breastfeeding is thought unlikely to cause short or long-term problems for your baby – especially if you wait 2 to 2½ or 3 hours per unit before breastfeeding again.1, 2
The expert’s view
“We know that alcohol does enter breastmilk in small amounts,” says GP Dr Una Duffy, “and that the more alcohol is taken, the higher the concentration of alcohol in the breastmilk will be. There are potential problems of this affecting the taste of the milk, and, at higher levels, your baby’s brain and the baby’s liver.”
But there is actually very little research on the effects of small amounts of alcohol in breastmilk – from drinking the occasional small glass of wine or beer, for example – on a developing baby: as Dr Una points out, “this is an area with lots of unknowns, as it is ethically hard to do research on breastfeeding mums and their babies.”
You may find your own GP and other experts advise you to avoid alcohol altogether while you’re breastfeeding – to eliminate any possible risk.
But Dr Una endorses the official NHS advice2 that a breastfeeding mother having the occasional drink is unlikely to cause their baby a problem, especially if you wait 2 to 3 hours before breastfeeding again. She says:
Ultimately, it’s your own personal decision. “It’s up to each mother either to accept a small potential risk or to play safe and have no risk at all,” says Dr Una.
Not sure how much a unit is?
One unit is the equivalent of:
- ½ pint of lower-strength lager, beer or cider
- ¼ pint of strong lager, beer or cider
- a single small (25ml) measure of a spirit such as vodka, gin or whisky
- 2/3 bottle of alcopop
What about wine? Be warned that 1 small glass of wine or champagne (125ml) is 1.5 units, a medium glass (175ml) is 2.1 units, and a large glass (250ml) is 3 units.
What’s the safest way to drink alcohol when I’m breastfeeding?
There are some steps you can take to reduce any risks to your baby when you have the occasional drink. These include:
- Wait until your baby is at least 3 months old. A newborn has a very immature liver and so more affected by alcohol; an older baby can metabolise alcohol more quickly.3, 4
- Express with a breast pump before you have a drink. You can store the milk and then use it when your baby next needs a feed.
- Don’t drink excessively. Keep to the safe level of 1-2 units.
- Eat when you have your drink. An alcoholic drink consumed with food decreases the absorption rate into the bloodstream.3
- Leave as long as possible between drinking and breastfeeding again. On average it takes around 2 hours for 1 unit of alcohol to leave your body’s bloodstream. However, no one woman is average – everyone’s metabolism is different.
- Don’t bedshare with your baby after having a drink. As we’ve said above (see The expert’s view), doing this has a strong association with sudden infant death syndrome (SIDS).2 Do remember that the rule applies whether you’re breastfeeding or not, so it’s also important for your partner not to bedshare if they have had a drink.
How long does it take for the alcohol to enter my breastmilk once I’ve had a drink?
The level of alcohol in your breastmilk is the same as the level of alcohol in your blood, and small amounts of alcohol will be in your breastmilk within 30 to 60 minutes of your starting to drink (a little longer if you’re eating as you drink).5
How long does it take for alcohol to leave my breastmilk after I’ve had a drink?
As alcohol leaves your bloodstream, it will also leave your breastmilk. So, as a general rule, it takes about 2 hours for the average woman to metabolise (get rid of) 1 unit of alcohol (and, therefore 4 hours for 2 drinks and so on).
This isn’t an exact science, though, as the rate of clearance depends on a whole range of factors, including your weight, your percentage of body fat, and the amount of food you’ve eaten. (If you really want to know more exactly what the clearance rate would be for your bodyweight, there are some useful charts published in a systematic review of alcohol and lactation carried out by Australian scientists in 2006.5)
There’s nothing you can do to speed up how fast the alcohol will leave your system: expressing your milk won’t help and, while they might make you feel better, nor will drinking a lot of water, resting or drinking coffee.6
There are some products available, though, including apps and alcohol-testing strips, that claim to tell you when your breastmilk is booze-free.
Should I ‘pump and dump’ help if I’ve drunk alcohol while breastfeeding?
You can if you want to – it’s a good way to relieve engorgement if you’ve missed a feed or 2 – but it’s important to understand that ‘pumping and dumping’ (expressing breastmilk after drinking alcohol and then throwing it away) won’t clear the alcohol out of your system any quicker.
Because, as we’ve seen, only time will reduce the amount of alcohol in your blood and breastmilk, any new milk you make to replace the milk you’ve expressed will still have some alcohol in it if there is still alcohol in your bloodstream.
Does drinking alcohol while you’re breastfeeding make my baby sleep better?
No, whatever the old wives’ tales say. In fact, it might actually make your baby’s sleep worse: a 2001 US study, for example, found that ‘breast-fed infants experience significantly less active sleep after exposure to alcohol in their mothers’ milk’. 7
Does drinking alcohol while you’re breastfeeding help my ‘let-down’ and milk flow?
No, it’s a (much-repeated) myth. You may hear tales of a daily Guinness helping you produce more milk, particularly in the ‘let-down’ process, when the milk starts to flow to your nipple but there’s very little evidence to support this.5 In contrast, many studies have consistently found that drinking while breastfeeding diminishes your milk supply.5
About our expert GP Dr Una Duffy
Dr Una Duffy is a GP and Chair of Bedfordshire and Hertforshire Local Medical Committee. She works in a busy practice in Luton and regularly advises women about pregnancy.
1. Drugs and Lactation database (LactMed): Alcohol. National Insitute of Health. Last updated July 20 2019.
2. Breastfeeding and drinking alcohol: NHS Online
3. Alcohol and breastfeeding (quick read): Laleche.org.uk
4. Breastfeeding and alcohol: Kellymom.com
5. Alcohol and lactation: a systematic review. Giglia and Binns. Nutritional Dietetics 63 103-116. First published 24 May 2006. DOI:10.1111/j.1747-0080.2006.00056.x
6. Alcohol metabolism. Bowling Green State University Dept of Wellness online.
7. Sleep disturbances after acute exposure to alcohol in mothers’ milk, Mennella JA et al. Alcohol, Volume 25, Issue 3, November 2001, Pages 153-15. DOI: 10.1016/S0741-8329(01)00175-6