Ovulation induction uses hormonal therapy to stimulate egg development and release, or ovulation. Historically, these drugs were designed to induce ovulation in women who did not ovulate on their own - typically women with irregular menstrual cycles. The goal was to produce a single, healthy egg.
The second use of ovulation induction was to increase the number of eggs reaching maturity in a single cycle, to increase chances for conception. The initial agents for this treatment - used first for in vitro fertilization (IVF) and only later for simpler treatments - were injectable medications. These agents carry an increased risk of multiple gestation, ovarian hyperstimulation, and increased cost and time commitment.
More recently, in the mid-90s, evidence developed to suggest there may be an advantage to treating even ovulatory women with fertility medications. These women with "unexplained infertility" may have subtle defects in ovulation, and medications may induce two to three eggs to mature, versus only one. However, for IVF medications dosage arranged to produce 7-8 eggs, this treatment therefore improves the quality and quantity of the ovulation, thus enhancing pregnancy rates.
In ovulatory women, ovulation induction is sometimes combined with intrauterine insemination. Ovulation induction should progress only after a complete and thorough evaluation. All underlying hormonal disorders, such as thyroid dysfunction, should be treated before resorting to ovulation induction with fertility drugs.