The term ovulation induction refers to the medical treatment of infertility caused by poor or absent ovulation. Ovulation disorders are associated with irregular or absent menstrual cycles.
Ovulation induction involves using hormones to stimulate ovulation and then advising couples when to have intercourse. In conjunction with the hormone treatment, patients are required to attend the clinic for regular blood tests and ultrasounds.
Two types of hormones may be used to stimulate ovulation: tablets (clomiphene citrate or letrozole) or injections of follicle stimulating hormone (FSH).
Clomiphene and letrozole both act early in the cycle against the hormone oestrogen, encouraging the pituitary gland at the base of the brain to produce higher levels of FSH than in a cycle with poor or no ovulation. That in turn stimulates ovarian follicular development. A course of tablets is given for five days - usually days two to six or five to nine of the cycle.
Follicle stimulating hormone (FSH) is the hormone necessary for the multiple follicular development required in IVF. It may also be used in smaller doses for ovulation induction. FSH is given by injection under the skin, with a fine needle.
When tablets are used, often the egg will release (ovulate) on its own and this will be detected on blood tests. However if this doesn’t occur, or if using FSH injections, when the lead follicle is the right size on ultrasound, ovulation is triggered with an injection of human chorionic gonadotrophin (hCG) – this mimics the natural LH surge that causes an egg to be released.
Even with the most careful monitoring, more follicles can reach maturity than desired. If this occurs, our Fertility Specialists will not advise intercourse as a multiple pregnancy is likely. These pregnancies are high risk – even with twins, complications are much more common than singleton pregnancies.
Ovulation induction may be recommended for women who have normal tubes, and whose partners have a normal semen analysis, but who rarely or never ovulate.
IUI is considered when donor sperm is required or for those who have a physical problem with sexual intercourse or a physical problem of the cervix preventing sperm penetration.
During an IUI cycle, we monitor patients closely with blood tests and ultrasounds and at the time of ovulation, place sperm directly into a woman's cervix using a small, thin plastic tube. Your Fertility Specialist may or may not prescribe ovarian stimulation in conjunction with IUI.
Ovarian stimulation combined with IUI is a common treatment worldwide for unexplained infertility, but is not as effective as IVF and has a higher risk for multiple pregnancy. Stimulation-IUI is also not as effective as IVF in cases where there is a low sperm count or endometriosis. It isn’t recommended if fallopian tubes are blocked or if the cause of infertility is unknown. As always, accurate diagnosis is imperative to ensure the tailored treatment plan addresses the fertility issue.