If a woman is not ovulating by herself then ovulation induction may be required. The most common causes of failure to ovulate are stress, weight fluctuations and Polycystic Ovarian Syndrome (PCOS). Other causes may include disorders of the pituitary gland, thyroid gland and raised prolactin levels. In some cases failure of ovulation is due to the ovarian failure. This may occur following treatment for cancer or may be the start of the menopause – premature ovarian failure. If ovulation does not occur, then medications may be administered with the onset of menstruation to stimulate egg production. If tablets are not effective then fertility injections may be necessary to stimulate egg production in the ovaries.
Ovulation is induced using one of two main drug regimens:
Clomiphene or Clomid tablets (alternatives are Tamoxifen and Letrozole tablets) increase the production of follicle stimulating hormone (FSH) by the pituitary gland, thereby stimulating follicles and hence egg growth. This tablet is normally taken from the 2nd to the 6th day of the period
Gonadotrophins: these are given by injection. Their active ingredient is follicle stimulating hormone. Examples are: Menopur, Gonal F and Puregon.. The response to any drugs given is monitored by ultrasound scans(follicle monitoring) from day 7 of menstrual cycleeither dailyor alternate days When follicles have reached an appropriate size intercourse is advised, or an injection of HCG is given to facilitate the timing of intercourse or IUI. Individual responses to treatment can be unpredictable and if, during the monitoring, the response is insufficient or too strong, the cycle may have to be cancelled and restarted as appropriate. If the response to the drugs is satisfactory, treatment usually continues for 6 cycles; treatment cycles can be carried out consecutively without a break. Potential side effects are mainly related to the drugs. Multiple pregnancies are a risk of ovulation induction treatments. Twins can result in up to 10% of cases with Clomiphene treatment, and 20% with gonadotrophins. Triplets may also occur in around 1% of cases. With careful monitoring the risk of multiple pregnancies is reduced but not eliminated.