Breast Milk Alcohol: When Can I Breastfeed After Drinking?

A glass of wine at a friend’s wedding, a beer after a long day with the baby — many nursing mothers ask: when is it safe to breastfeed again? The answer is reassuringly simple: alcohol in breast milk mirrors blood alcohol concentration (BAC), and your liver clears it at roughly 0.015% per hour.

This guide explains what the science says, what the AAP and CDC recommend — and exactly when your milk is alcohol-free.

How alcohol enters breast milk

Alcohol is water-soluble and passes the blood-milk barrier passively and freely. Concentration in milk is roughly identical to the level in blood (ratio ≈ 1:1). A 0.05% BAC means about 0.05% alcohol in breast milk.

The peak level occurs 30–60 minutes after drinking — faster on an empty stomach, slower after food. As the liver metabolizes alcohol, milk concentration falls in step.

The Widmark formula for nursing mothers

Because milk alcohol equals blood alcohol, the same equation applies:

Alcohol (g) = Volume (ml) × (ABV / 100) × 0.8

Peak BAC = Alcohol (g) / (Body weight × 0.55)

Current BAC = Peak − (0.015% × Hours)

The Widmark factor of 0.55 reflects body water in women. Elimination is linear at ~0.015% BAC per hour — coffee, exercise, and water do not change it.

Worked example: 1 glass of wine

Step	Calculation
Drink	5 oz (150 ml) wine, 12% ABV
Alcohol	150 × 0.12 × 0.8 = 14.4 g
Peak BAC (60 kg / 130 lb)	14.4 / (60 × 0.55) = 0.044%
Clearance time	0.044 / 0.015 = about 2 hrs 55 min

After just under 3 hours, breast milk is alcohol-free again.

Rule of thumb: per standard drink

Drink	Clearance (60 kg / 130 lb)
1 beer (12 oz, 5%)	~2 hrs
1 glass wine (5 oz, 12%)	~2 hrs 15 min
1 shot spirits (1.5 oz, 40%)	~2 hrs
1 glass sparkling wine (100 ml)	~1 hr 25 min

What AAP, CDC and WHO recommend

The American Academy of Pediatrics (AAP), CDC and WHO recommend avoiding alcohol entirely while breastfeeding. Studies suggest measurable effects on infant sleep architecture and motor development at higher exposures.

Occasional moderate drinking (one drink) with adequate clearance time is generally considered acceptable. Most experts agree: pumping and dumping does NOT speed elimination. Alcohol stays in your bloodstream until your liver metabolizes it; freshly produced milk will contain alcohol again until then.

Common myths

Myth: Pumping removes the alcohol

False. As long as alcohol circulates in your bloodstream, every new portion of milk will contain alcohol. Only time clears it.

Myth: Beer increases milk supply

Alcohol actually suppresses oxytocin and can briefly reduce milk volume. The hops, not the alcohol, may have a mild effect — non-alcoholic beer or hops tea is the better choice.

Myth: Coffee or exercise clears alcohol faster

False. Your liver metabolizes alcohol at ~0.015% BAC per hour — independent of caffeine, activity, or hydration.

Calculate when your milk is alcohol-free

Personal estimate from weight, drinks and time — free, instant, no sign-up.

Open the calculator →

Related calculators

For general blood alcohol estimates, try our Blood Alcohol Calculator. To convert drinks into UK/US units, see the Alcohol Units Guide. If you’re still pregnant, our Pregnancy Weight Gain Guide tracks healthy ranges by trimester.

Bottom line

Alcohol while breastfeeding is not trivial — but it is predictable. The Widmark formula tells you when alcohol has cleared and nursing is safe again. The fastest way: open the Breast Milk Alcohol Calculator, enter weight, drink, and time — done.