Women who wear contact lenses may need to change their prescription or may be unable to use that type of lens. Some women develop high blood pressure while taking oral contraceptives, which ordinarily returns to the original levels when the oral contraceptive is stopped. You should consult your physician before resuming use of oral contraceptives after childbirth, especially if you plan to nurse your baby. The drugs in oral contraceptives are known to appear in the milk, and long-range effect on infants is not known at this time. Furthermore, oral contraceptives may cause a decrease in your milk supply as well as in the quality of the milk.
Blood clots are the most common of the serious side effects of oral contraceptives.
There is evidence that the risk of clotting increases with higher estrogen doses. Furthermore, cigarette smoking by oral contraceptive users increases the risk of serious adverse effects on the heart and blood vessels. The risk of abnormal blood clotting increases with age in both users and nonusers of oral contraceptives, but the increased risk from oral contraceptives appears to be present at all ages. Formation of tumors. Studies have found that when certain animals are given the female sex hormone estrogen continuously for long periods, cancers may develop in the breast, cervix, vagina and liver.