Hi, Thanks for the query, Nostra is a progestogen and can be used to treat premenstrual syndrome, painful periods, etc Krimson 35 is a drug used mainly in PCOS due to its antiandrogen action. It also acts as a oral contraceptive but not prescribed for that purpose. So you will not get pregnant while on this drug. It is contraindicated during pregnancy and lactation. It has no effects on future pregnancies. Take care.. Hope it helps you..