Answer is D (Propylthiouracil): Propylthiouracil (PTU) is not associated with an increased risk of congenital malformations and is considered the drug of choice for treating hypehyroidism is Pregnancy. Hypehyroidism in Pregnancy Maternal Hypehyroidism in Pregnancy is usually due to Grave's Disease. TRAb crosses the placenta and if mother is thyrotoxic it must be assumed that the foetus is similarly affected The treatment of choice for thyrotoxicosis in Pregnancy is therapy with safe Antithyroid Drugs Thionamides (Carbimazole/Propylthiouracil) are equally effective in controlling Grave's Hypehyroidism in Pregnancy and are considered the drugs of choice. Amongst Carbimazole (Methimazole) and Propylthiouracil, Propylthiouracil is typically the preferred agent (Traditional drug of choice) Radioactive Iodine Therapy is contraindicated in pregnancy as it may destroy the fetal thyroid Thyroidectomy (Surgery) is rarely required during Pregnancy. When indicated preoperative treatment with antithyroid drugs and iodine is undeaken and surgery is performed during the second trimester Propylthiouracil Effective in controlling Grave's Hypehyroidism in Pregnancy Not associated with increased risk of congenital malformation (Aplasia Cutis Congenita has not repoed with the use of Propylthiouracil)) Considered the drug of choice for treatment of Hypehyroidism in pregnancy Considered the drug of choice for mothers during Breast feeding (Transferred to the milk one tenth as much as Carbimazole) Effective in controlling Grave's Hypehyroidism in Pregnancy Aplasia Cutis Congenita is a rare disorder repoed in neonates of mothers who received Methimazole (Carbimazole) during pregnancy. (Consensus: Insufficient data to establish a direct causal relationship) Considered as an effective alternative where Propylthiouracil is not available or cannot be used for any reason May be used in mothers during breast feeding at a low dose (Transferred to milk more than Propylthiouracil but usually does not adversely affect the infant's thyroid function)