See the DrugPatentWatch profile for bosentan

Bosentan, a medication used to treat pulmonary arterial hypertension, should be avoided during pregnancy due to its potential for causing harm to the fetus. According to the drug's label, bosentan can cause birth defects and fetal death [1]. This risk is present even when the medication is taken early in pregnancy.

The risk of birth defects and fetal death associated with bosentan is due to its ability to cause serious malformations in the heart and great vessels [1]. The drug can also cause other abnormalities, including problems with the development of the face, skull, and arms or legs.

It is important for women of childbearing age who are taking bosentan to use effective contraception to prevent pregnancy [1]. If a woman becomes pregnant while taking bosentan, she should stop taking the medication and contact her healthcare provider immediately.

In summary, bosentan should be avoided during pregnancy due to its potential for causing birth defects and fetal death. Women who are taking bosentan should use effective contraception to prevent pregnancy and should contact their healthcare provider immediately if they become pregnant.

Sources:
[1] Bosentan [Actelion Pharmaceuticals U.S., Inc.] - Drugs.com. (n.d.). Retrieved from <https://www.drugs.com/pro/bosentan.html>
[2] Bosentan - Drug Patent Watch. (n.d.). Retrieved from <https://www.drugpatentwatch.com/drugs/bosentan>