Skip to main content

Hydrochlorothiazide / methyldopa Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Aug 4, 2022.

Hydrochlorothiazide / methyldopa is also known as: Aldoril, Aldoril 15, Aldoril 25, Aldoril D30, Aldoril D50

Hydrochlorothiazide / methyldopa Pregnancy Warnings

Animal studies have failed to reveal evidence of fetal harm. In humans, treatment with methyldopa has revealed improved fetal outcome as well as reduced infant average head circumference (0.4 cm). There are no controlled data in the first trimester of human pregnancy; there are no controlled data for hydrochlorothiazide in the second and third trimesters.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

This drug should be used during pregnancy only if clearly needed.

US FDA pregnancy category: C

See references

Hydrochlorothiazide / methyldopa Breastfeeding Warnings

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (hydrochlorothiazide, methyldopa [in small amounts])

Comments: According to some experts, the individual components of this drug can be used safely during lactation; hydrochlorothiazide 50 mg per day or less is considered acceptable during lactation while no special precautions are required for methyldopa.

See references

References for pregnancy information

  1. "Product Information. Aldoril 25 (hydrochlorothiazide-methyldopa)." Merck & Co., Inc

References for breastfeeding information

  1. "Product Information. Aldoril 25 (hydrochlorothiazide-methyldopa)." Merck & Co., Inc
  2. United States National Library of Medicine "Toxnet. Toxicology Data Network." (2013):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.