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Alcohol or other drug use during pregnancy and breastfeeding

Description

Using any amount of alcohol or other drugs during pregnancy and while breastfeeding can affect the health and development of the infant.

Several factors, such as the type of psychoactive substances used, the pregnant person’s characteristics or their alcohol or drug use habits, contribute to the risk of harmful effects for the fetus or baby.

Possible consequences of alcohol use during pregnancy

Alcohol passes, in almost the same concentration, directly from the pregnant person’s bloodstream to the fetus’s through the placenta. So drinking alcohol during pregnancy can have serious consequences for the pregnancy and the unborn baby. Alcohol use can affect fetus development at any stage of a woman’s pregnancy, regardless of the type of alcohol (beer, wine or spirits), amount and frequency of use. The brain of a fetus is particularly vulnerable to alcohol.

When a pregnant woman drinks alcohol, she is believed to have a higher risk of the following:

  • Miscarriages
  • Premature births
  • Perinatal death (stillbirth)
  • That her child will have congenital anomalies
  • That her child will have fetal alcohol spectrum disorder

Some people may have consumed alcohol in early pregnancy, before they knew they were pregnant. If you are unsure or worried about this, talk to a health professional or call Info‑Santé 811.

Possible consequences of alcohol use during breastfeeding

Alcohol consumed by a person is found in the milk they produce, at concentrations similar to those present in their blood. These concentrations in milk decrease as the blood removes the alcohol.

Drinking any amount of alcohol while breastfeeding can:

  • reduce milk production
  • reduce the ejection reflex
  • disrupt your baby's sleep

Regular drinking while breastfeeding can result in:

  • poor weight gain for the baby
  • negative effects on their intellectual and physical development

Possible consequences of drug use during pregnancy

Psychoactive substances used during pregnancy can cross the placenta. So, drug use during pregnancy can affect certain aspects of fetal development.

In particular, the neurocognitive development of the unborn baby can be disrupted in the medium and long term. The baby might experience mild cognitive impairment, language difficulties, behavioural disorders or hyperactivity.

Using drugs during pregnancy can also lead to a risk of transmitting viral infections to the baby such as hepatitis B, hepatitis C or HIV if the drug used is injected with a needle or syringe used by an infected person.

Some people may have used drugs in early pregnancy, before they knew they were pregnant.

If you are unsure or worried about this, talk to a health professional or call Info‑Santé 811.

Cannabis

To find out more about the risks of using cannabis during pregnancy, read the Risks during pregnancy and while breastfeeding section of the page Health risks of cannabis use.

Possible consequences of drug use during breastfeeding

The production, quantity and composition of milk can be disturbed by using psychoactive substances while breastfeeding. In addition, the drugs used can pass into the breast milk.

The possible consequences of exposing the baby to drugs through breast milk depend on several factors, such as the substance, the amount used and the health of the user and the baby.

For more details, consult a health-care professional or call Info-Santé 811.

Cannabis

To find out more about the risks of using cannabis during breastfeeding, read the Risks during pregnancy and while breastfeeding section of the page Health risks of cannabis use.

Recommendations related to alcohol or other drug use

During pregnancy

There is no safe threshold for alcohol use during pregnancy. So the precautionary principle must apply: it is recommended not to drink any amount of alcohol at any time during pregnancy.

Because of the risks for both the pregnant person and the unborn baby, it is also recommended not to use drugs during pregnancy.

The partner and the family can support the pregnant person during this period of abstinence, in particular by:

  • planning other activities to relax or have fun (reading, walking, cinema, etc.)
  • avoiding encouraging them to use alcohol and other drugs during activities
  • offering the possibility of drinking non alcoholic beverages
  • changing their own alcohol and drug use (cutting down or quitting) during this time

While breastfeeding

The benefits of breastfeeding outweigh the risks associated with low alcohol use. A breastfeeding person may drink alcohol while taking the following precautions to avoid exposing the baby:

  • drink alcohol occasionally, in small quantities
  • breastfeed just before having a standard drink of alcohol
  • after having a standard drink of alcohol, wait two to three hours before breastfeeding again
  • if having more than one standard glass of alcohol, use breast milk that has been expressed in advance
  • discard the milk produced during this time

Drugs used by a breastfeeding person can pass into breast milk and expose the child to these substances, resulting in health risks.

Therefore, it is recommended not to use drugs while breastfeeding.

Help and resources

If you're concerned about your alcohol or drug use, do not hesitate to talk to a health-care professional for support and advice.

To get help or more information, contact one of the following resources:

Last update: March 12, 2026

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