Clomiphene can cause enlargement of the ovaries and sometimes this causes a crampy pain or a sudden sharp pain if a large follicle suddenly bursts. As with many drugs, some patients develop a rash. More specific side effects are mild visual disturbances and hot flushes. Thinning of the hair is also listed as a side effect but I have never seen this. Clomiphene may theoretically increase the risk of ovarian cancer if taken for long periods. It may also have an effect on the uterus or the cervix to reduce fertility in women who are ovulating naturally. There are alternatives to clomiphene and if side effects develop, different tablets or injections are sometimes given.