Medical condition	Medication guidelines	Comments
Acne	Isotretinoin should be avoided	Isotretinoin is associated with miscarriage and birth defects¹
Asthma	Inhaled corticosteroids and beta agonists are preferred	Use of oral corticosteroids in the first trimester is associated with reduced birth weight, increased risk of oral cleft, and higher rates of preeclampsia³⁵ Inhaled corticosteroids are recommended for preventive treatment and may avoid the need for oral treatment³⁶ When oral corticosteroids are indicated for treatment of severe asthma, the risk of uncontrolled severe asthma to the mother and fetus is greater than the risk of oral corticosteroids³⁷
Diabetes mellitus	Most oral antidiabetic agents should be discontinued and insulin started; metformin (Glucophage) may be continued in the preconception period³⁰	ACE inhibitors and ARBs are associated with fetal renal anomalies and fetal death^37,38 Adverse effects in animal studies; limited data in humans³⁸
Diabetes mellitus	ACE inhibitors, ARBs, and statins should be avoided
Hypertension	ACE inhibitors, ARBs, and atenolol (Tenormin) should be avoided	ACE inhibitors and ARBs are associated with fetal renal anomalies and fetal death^37,38; adverse effects in animal studies, limited data in humans³⁸ Atenolol is associated with lower birth weight³⁹
Hyperthyroidism	Propylthiouracil is preferred in the first trimester; methimazole (Tapazole) is preferred in the second and third trimesters	Possible teratogenicity in the first trimester with methimazole; propylthiouracil-associated hepatotoxicity in subsequent trimesters⁴⁰
Seizure disorder	Many major antiepileptic drugs (e.g., valproate [Depacon], phenytoin [Dilantin], carbamazepine (Tegretol), phenobarbital) are teratogenic	Rates of congenital anomalies are related to higher doses and polytherapy Monotherapy should be used when possible at the lowest effective dosage^6,41
Thrombophilia	Heparin or low-molecular-weight heparin is preferred	Warfarin is teratogenic^1,37,42
Thrombophilia	Warfarin (Coumadin) should be avoided	Warfarin is teratogenic^1,37,42