Hi, Thanks for posting in HCM. I understand your concern. Duphaston contains dydrogesterone , which is a synthetic progesterone It is used to treat a conditions resulting from a lack of endogenous (naturally produced) progesterone. Since your wife has a history of miscarriage in the previous pregnancy, duphaston has been given as it would prevent miscarriage from happening. The most frequently reported side effects when taking duphaston include: nausea, abdominal bloating, breast pain, dizziness, weight gain and skin rash. However, not everyone taking this medications would experience all the above mentioned side effects. Since it is beneficial in continuing pregnancy and prevents miscarriage, it is advisable to take the medication as advised and do the necessary follow-up as suggested. Hope the information provided would be helpful. All the best.