Mefloquine is used primarily for malaria prophylaxis in regions of chloroquine/proguanil resistance and is recommended by the Royal College of Obstetricians and Gynaecologists (RCOG) and the UK Health Security Agency (UKHSA) as a first-line option for prophylaxis during the second and third trimester of pregnancy (in non-resistant regions). UKHSA guidance also states that mefloquine use may also be justified in the first trimester after a careful risk assessment and discussion with the patient. Due to increased mefloquine resistance in some locations and the risk of neuropsychiatric side effects, it is now rarely used to treat malaria in monotherapy but may still be used on occasion in combination with artemisinin-based therapies.
Travel to areas where malaria is endemic should be avoided during pregnancy wherever possible. If travel to such areas is unavoidable, insect repellents, bed nets, appropriate clothing to prevent mosquito bites and adequate chemoprophylaxis should be used.
Human pregnancy data concerning both prophylaxis and treatment with mefloquine provide no conclusive evidence of an increased risk of miscarriage, congenital malformation, stillbirth/IUD, low birth weight, prematurity, growth restriction, infant mortality or delayed neurodevelopment. However, data relating to first trimester exposure are limited; as such, increased risks of congenital malformation or miscarriage cannot currently be completely excluded.
Where mefloquine is clinically indicated, it should not be withheld on account of pregnancy as the known risks of maternal malaria infection are likely to be far greater than any potential risks to the fetus from the drug.
Exposure to mefloquine at any stage of pregnancy in the absence of maternal malaria infection would not usually be regarded as an indication for 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.
Important: Please ensure that the selected antimalarial will provide appropriate prophylaxis for the area of travel. Advice is available from a number of sources (e.g. WHO, BNF, Fit For Travel, Travel Health Pro, RCOG, UKHSA and TRAVAX).
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.