Is Mifepristone safe while breastfeeding?

Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Mifepristone. This is a summary of that source — not our own verdict.

Effects on the breastfed infant

Relevant published information was not found as of the revision date.

Effects on milk supply

Based on animal data, some authors suggest that mifepristone used at term might shorten the onset of lactation, increase milk flow and increase the initial growth rate of breastfed infants.[ 2 - 4 ] However, no human data are available.

Levels in milk

Maternal Levels. Twelve women (most 6 to 12 months postpartum) who had undergone a medical abortion using mifepristone and misoprostol provided milk samples for up to 5 days after the procedure for measurement of mifepristone. In the 2 women who received a single dose of 200 mg orally, mifepristone was undetectable ( 5.6 mcg/L) in breastmilk at all times. Among the 10 women who received a single oral dose of 600 mg, average mifepristone breastmilk levels were 172 mcg/L on day 1 (n = 9) ; 66 mcg/L on day 2 (n = 9); 31 mcg/L on day 3 (n = 10); 24 mcg/L on day 4 (n = 4); and 25 mcg/L on day 5 (n = 3). Breastmilk levels of mifepristone were highest in the samples collected between 6 and 9 hours after drug administration. Samples collected between 9 and 15 hours after the dose had much lower mifepristone levels. The authors estimated that a fully breastfed infant would receive a weight-adjusted dosage of 0.5% of the maternal dosage. They suggested that breastfeeding need not be interrupted after a single dose of mifepristone and that a dose of 200 mg might be preferable to a 600 mg dose in nursing mothers.[ 1 ] Infant Levels. Relevant published information was not found as of the revision date.

Source: NIH LactMed (National Library of Medicine).

Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.