Is Pyrethrins safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Pyrethrins. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Because absorption after topical application is very limited, occasional pyrethrins and piperonyl butoxide use is acceptable in nursing mothers. Extensive exposure, such as from agricultural use or malaria control might have long-term health concerns because residues can be found in breastmilk.[1] Only water-miscible cream, gel or liquid products should be applied to the breast because ointments may expose the infant to high levels of mineral paraffins via licking.[2]
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. Pyrethrins were measured in 53 breastmilk samples from 29 mothers collected 1998 to 1999 in Basel Switzerland. Pyrethrins were detected in 42 milk samples, even in mothers from households that reported no pyrethrin use. The average pyrethrins concentration was 89 mcg/kg of fat (range undetectable [<25 mcg/kg] to 341 mcg/kg fat).[3]
Pyrethroids (permethrin, cyfluthrin, cypermethrin and deltamethrin) were found in the breastmilk of nursing mothers in 3 South African towns. Average levels in breastmilk ranged from 8.3 to 48.4 mcg/L in the 3 towns. The source was thought to be from a dusting powder widely available and used in gardening. The dosage and route of exposure (i.e., topical, inhalation, oral) could not be determined. All milk levels were below the allowable daily limit for permethrin.[4,5]
Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
“No published information” means the studies do not exist yet — not that Pyrethrins is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Pyrethrins” (LM734). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.