Head lice (Pediculus humanus capitis) are parasitic insects that infest the hairs of the human head and feed on blood from the scalp. Head lice can be treated by ‘wet combing’ or with medicated lotions or sprays consisting of either silicone- or fatty acid ester-based preparations, or chemical insecticides. Crème rinses and shampoos are not considered effective and are therefore not recommended in the treatment of head lice.
There are very limited human data on safety during pregnancy of any of the medicinal products used in the treatment of head lice. It is currently recommended that pregnant women use either wet combing or 4% dimeticone lotion, which is licensed for use during pregnancy and breastfeeding. Data regarding malathion (the only chemical insecticide recommended in the UK for the treatment of head lice) do not provide evidence of fetal harm, but their limited nature means that firm conclusions cannot be drawn.
Exposure to head lice treatments at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.
This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.
If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.
If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.