Ovulation Induction

Use of pills or injections to assist the growth and maturation of eggs leading to ovulation in women with anovulation (lack of natural ovulation). Ovulation induction can be combined with Timed Sexual Intercourse or with Intrauterine Insemination (IUI).

Ovulation induction is the process of using prescribed fertility medications to stimulate the ovaries into releasing an egg. Most commonly, the treatment will be offered to patients who are experiencing problems with irregular periods or are even missing them entirely. The latter of these issues is also known as “anovulation”.

Typically, ovulation will occur when one of a person’s ovaries releases a mature egg. This is done in preparation for the egg to be fertilised by sperm cells, and the egg will travel from its ovary down through the fallopian tubes and into the uterus. If it has been fertilised in this time, it will implant itself in the uterine lining and start to grow into an embryo. If it has not been fertilised, the uterus lining will eventually shed and the egg will be expelled from the body during the person’s next period.

This is all part of a normal menstrual cycle, and the process of ovulation should repeat itself roughly once every 28 days. There may be fluctuations in this time frame, however, and it is also considered acceptable if ovulation occurs between every 21 and every 35 days. If ovulation happens less than once every 35 days or has been noted to be unpredictable, then the person’s cycle can be considered irregular. When no pattern can be established in a person’s cycle for months, this is known as “oligoovulation”. 

The goal of ovulation induction is to ensure a person’s ovaries will release an egg, either so that they may conceive a child naturally or so that the egg may be collected for use in fertility treatment. If tests and assessments have concluded that the patient is likely to respond well to a series of medications, then these may be administered to ensure ovulation occurs.

Ovulation induction may be carried out using one of two main drug regimens: 

  • Clomiphene or Clomid tablets, which increase the production of the follicle-stimulating hormone (FSH), thereby stimulating the follicles and encouraging eggs to grow and mature
  • Gonadotropin injections, which have FSH as an active ingredient

Once one of these courses of treatment have been decided upon and given, the patient will be monitored by a specialist using ultrasound scans. When the patient’s follicles have reached an appropriate size, they may then be advised to start having intercourse to try and conceive naturally. Alternatively, a “trigger” shot of human chorionic gonadotropin (hCG) may be given to help take them to the next step in fertility treatment.

Potential side effects from the treatment are mainly related to the particular drug used, but it should also be noted that ovulation induction does give a greater chance of multiple pregnancies. According to the NHS, twins can result in up to 10% of cases with Clomiphene treatment and up to 20% with gonadotropins. Triplets may occur in around 1% of cases. This risk is reduced with careful monitoring, but it cannot be eliminated as a possibility.