Reproductive Health PH, Pregnancy and Contraception Pulmonary hypertension (PH) patients should avoid becoming pregnant because of the dangerous risks involved. Medications used to treat pulmonary arterial hypertension, such as ambrisentan, bosentan, macitentan and riociquat, are toxic to fetuses. Discontinuing the medication puts the mother at risk of worsening PH. Some blood thinners increase the