Design: Descriptive observational study of pharmacovigilance queries
Population: 2,473 breastfeeding medication queries to the Lyon pharmacovigilance centre, 2019–2023
Primary outcome: Recommendation given on medication and breastfeeding
Effect: 87% supported breastfeeding; 13% advised stopping drug or breastfeeding

The Lyon pharmacovigilance centre reviewed all 2,473 queries about medicines during breastfeeding that it handled from 2019 to 2023, about 500 a year. Most came from mothers themselves (44%), allied health professionals (29%) or specialists (25%).

In 87% of cases the centre supported breastfeeding, either outright or with conditions such as monitoring the infant, adjusting the dose or timing feeds. Only 13% led to advice to stop either the medicine or breastfeeding, because of a formal contraindication, little benefit from the drug, or too little safety data. Polypharmacy, present in 35%, was linked to more restrictive advice. Chronic treatments such as antihypertensives, antiepileptics and psychotropics made up 36%. Reported infant adverse effects were rare and not serious.

The practical message is that the default should be to find a way to keep both the treatment and breastfeeding. Mothers are often told to stop one or the other unnecessarily, and a specialist information service can usually find a compatible option.

Most maternal medicines are compatible with breastfeeding, with or without simple precautions.
Before advising a mother to stop breastfeeding, check a lactation drug resource or pharmacovigilance service.
Multiple concurrent medicines were linked to more restrictive advice; review whether each is needed.
Where caution is needed, monitoring the infant or timing doses after feeds often allows both to continue.
Antihypertensives, antiepileptics and psychotropics were common queries; choose agents with established lactation data.

Why it matters

Unnecessary advice to stop breastfeeding or a needed medicine is common, and avoidable.

The statistics, in plain English

These are descriptive proportions of queries to one service, not measured infant outcomes. 'Rare and non-serious' adverse effects reflect what was reported, which will understate milder effects.