Irregular ovulation is the cause of 30-40% of cases of infertility. Irregular periods, the absence of periods, or abnormal bleeding can indicate anovulation, the failure of the ovary to realize an egg.
Ovulation can usually be induced through the use of fertility drugs, such as clomiphene (brand name: Clomid or Serophene). Clomiphene is typically the first medication tried because it has a long history of effectiveness and can be taken orally, rather than by injection. A typical course of clomiphene is up to three to six months.
Other fertility drugs are available if needed. Most of these are hormones that are administered by injection.