Alcohol and breastfeeding – advice

Alcohol consumption for breastfeeding mothers is not recommended, but it is not completely forbidden either. Alcohol is on the list of foods to avoid while breastfeeding, it should remain very occasional and moderate. Around half of breastfeeding women in Western countries consume alcohol while breastfeeding [1]. 

The American Journal of Paediatrics recommends that the intake of alcoholic drinks be kept to a minimum and limited to occasional consumption. It is preferable not to exceed 0.5 g of alcohol per kg of body weight, which, for a mother weighing 60 kg, corresponds to approximately 6 cL of spirits, 24 cL of wine or 2 beers [2]. The best option remains choosing non-alcoholic versions, and looking for alcohol-free cocktail recipes.

Alcohol passes freely into breast milk by diffusion, at roughly the same concentrations as in the maternal bloodstream, and the concentration decreases linearly at the same rate as in the blood [3]. 

The toxic metabolite of alcohol, acetaldehyde, does not appear to be excreted into breast milk, even at high concentrations in the maternal bloodstream [4]. 

Studies have shown that consuming around 3 drinks results in an alcohol concentration in breast milk that would expose the baby to approximately 5–6% of the maternal dose, if the baby is fed at the point when the alcohol concentration in the milk is at its peak [5]. The baby is therefore only exposed to a fraction of the alcohol dose ingested by the mother [6]. 

Blood alcohol levels will vary depending on the amount of alcohol consumed, the alcoholic strength of the drink, how quickly it is consumed, whether the stomach is full or empty, and also according to the mother's body fat percentage and weight. 

For a mother weighing 60 kg who drinks a standard 10 cl glass of wine at 12% alcohol (roughly equivalent to a standard 25 cl serving of beer at 5%), the alcohol level in the bloodstream — and therefore in breast milk — is 0.27 g of pure alcohol per litre of milk, or 0.027%, which is lower than the 0.05% threshold considered alcohol-free. 

If a 4 kg infant drinks 150 ml of this milk, their blood alcohol level will be 0.014 g of alcohol per litre of blood (for comparison, the drink-drive limit in France for a new driver is 0.2 g per litre of blood).

But saying "it's fine, I can drink every day because my milk contains less alcohol than an alcohol-free beer" doesn't hold up, because…

Newborns metabolise alcohol approximately half as quickly as adults, as they have limited liver function. Even a small amount of alcohol can therefore put a strain on their liver. 

A newborn's blood volume is approximately 20 times lower that of an adult's blood volume.

In terms of volume, a baby actually drinks far more milk than a single glass (on average, they drink 750 ml of milk from 1 to 6 months, and this amount varies little up to 12 months).

Alcohol primarily affects you — your alertness may be reduced and your reflexes impaired, in which case bed-sharing (co-sleeping) is not recommended [9]. 

If you plan to drink, you should breastfeed before consuming alcohol, or wait the necessary time for it to be eliminated from your body. You can also use a breast pump beforehand if you wish.  

Breastfeeding is controlled by two hormones: prolactin and oxytocin. Prolactin stimulates lactation, and oxytocin causes the smooth muscle cells surrounding the breast tissue to contract, thereby producing the ejection of milk stored in the breast. Alcohol consumption inhibits the milk ejection reflex, leading to a temporary reduction in lactation [10]. Indeed, alcohol inhibits oxytocin — and therefore the milk ejection reflex — in a dose-dependent manner.

One study showed that the volume of expressed milk was on average 9.3% lower in the two hours following alcohol consumption [11].

In the event of a prolonged drop in milk production, you may wish to turn to a breastfeeding-compatible food supplement to support your milk production. 

Although your baby is only exposed to a fraction of the alcohol you drink, this can pose risks to their health.

As the rate of elimination is constant and independent of alcohol concentration, drinking water, resting or "pumping and dumping" breast milk does not speed up elimination [20]. 

Unlike urine, which stores substances in the bladder, alcohol is not trapped in breast milk, but is continuously eliminated as it diffuses back into the bloodstream. As a result, the level of alcohol present in breast milk decreases as it decreases in the bloodstream. The only way to eliminate alcohol is to wait.

It is generally recommended to wait between 2 and 3 hours before giving your milk to ensure the alcohol has completely left the body [20].

To ensure the complete elimination of alcohol from milk, mothers can consult a nomogram developed by the Canadian Motherisk programme, which determines the time needed based on the mother's weight and what was consumed [21].

You can also calculate the elimination time yourself by using the calculation above to estimate your blood alcohol level and dividing it by 0.15 (based on an average alcohol elimination rate of 15 mg/dL/h). 

You can also use test strips such as Milkscreen to determine whether your breast milk contains alcohol. 

Fancy an alcohol-free cocktail? Discover our recipe for a carrot cocktail.