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Ovulation Induction (OI)

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 a woman has an irregular menstrual cycle, monitoring with ultrasound scans (follicle tracking) and hormone assessments may help to identify the fertile time of the month and so improve the chances of natural conception.

Before ovulation problems can be treated it is important to undertake certain tests to establish the cause. These tests include an ultrasound scan of the ovaries and womb and blood tests to measure a range of hormones including thyroid, prolactin, FSH, LH, Testosterone and other androgens (male hormones). It is also important to ensure that the ovary is capable of responding to the drug treatment. One possible cause of failed ovulation is ovarian failure more commonly known as the menopause. If the FSH (> 10) concentration level is high and the AMH concentration is low when measured at the start of a period, ovarian failure is likely. In such cases fertility treatment is less successful.

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 more powerful 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 given in a starting dose of 50 mgs (1 tablet) taken from the 2nd to the 6th day of the period. If the periods are very infrequent then it may be necessary to induce a period by giving a different type of tablet called Norethisterone.
  • Gonadotrophins: these are given by injection. Their active ingredient is follicle stimulating hormone. Examples are: Menopur, Gonal F and Bemfola. These injections are given on a daily basis and start at a dose of 75 IU each day.

The response to any drugs given is monitored by ultrasound scans. 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.

Other treatments for women with PCOS

Women with PCOS who are not ovulating are normally given Clomid as first line treatment and usually respond very well to this. Two other treatment options may be used:

  • Metformin - this is a medication used in the treatment of Diabetes which has the benefit of improving ovulation in some women with PCOS. This is because PCOS is known to affect insulin and glucose metabolism.
  • Ovarian drilling. This is a surgical treatment that requires a laparoscopy to be carried out. 4mm length holes (usually 4 per ovary) are drilled into the ovary to help improve ovulation. This procedure may trigger natural ovulation to occur in about 60% to 85% of women with PCOS. This is an invasive procedure which carries the risks of laparoscopy. Rarely causes scar tissue to form in the area of the ovary.