Diuretics are given to reduce oedema and used in the management of heart failure and other conditions associated with fluid overload. They are also used to treat hypertension, although are generally contraindicated in pregnancy for this sole purpose. This document focuses on the diuretics amiloride, chlorothiazide, furosemide and spironolactone, which are among some of the more commonly prescribed diuretics for which there is pregnancy outcome data
Diuretics are not routinely recommended in pregnancy due to the potential risk of altered uteroplacental blood flow, and in the case of spironolactone and eplerenone, antiandrogenic effects which could theoretically affect the development of a male fetus. However, their use may be justified under specialist supervision in cases of severe maternal illness for which other treatments are likely to be ineffective or have to be discontinued due to pregnancy (such as an ACE-inhibitor or ARB).
There are few controlled studies of diuretic use during pregnancy, and for each individual diuretic; data are therefore limited. The decision to use a diuretic during pregnancy is clinical, based on the benefits of effectively treating the maternal condition versus the possible risks to the fetus. Where a diuretic is being used to treat a life-threatening condition or is prescribed to replace a drug with established adverse fetal effects (such as an ACE-inhibitor or ARB), the benefits of treatment are likely to outweigh the possible risks.
Women being treated with a diuretic who are either planning a pregnancy or become pregnant should be offered a medication review by their specialist.
Exposure to a diuretic at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy. Additional monitoring of fetal and maternal wellbeing is advised. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome and therefore the need for additional monitoring.
Data relating to diuretic use in pregnancy are limited. Clinicians treating pregnant women with diuretics are therefore encouraged to report any exposures to UKTIS to facilitate surveillance of pregnancy outcomes.
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.