Ovulation induction involves taking medication to induce ovulation by encouraging eggs to develop in the ovaries and be released, increasing the chance of conception through timed intercourse or artificial insemination.
It is most suitable for women who are producing low levels of hormones for ovulation or who are not ovulating at all but have normal fallopian tubes and the male partner has a normal semen analysis.
Medications used in ovulation induction can include:
- Clomiphene Citrate (Clomid)
An oral medication used to induce ovulation in women who do not ovulate on their own by encouraging the body to produce more follicle stimulate hormone (FSH). Most commonly used if a woman has irregular or long menstrual cycles.
- Injectable Gonadotropins
These are natural hormones secreted by the pituitary gland. In the natural cycle, they stimulate the ovaries to produce and mature eggs (ovulate). When given in injection form, they stimulate the ovaries to produce and mature eggs as well, and to overcome the natural response of the ovaries to produce only a single mature egg in the natural cycle.
Daily injection of gonadotropins for 7-10 days is used to correct ovulation problems and produce more than one egg. Gonadotropin ovulation induction treatment cycle, also known as Controlled Ovarian Hyperstimulation (COH), requires careful monitoring of the ovaries with ultrasounds and blood hormone levels every other day.
When the eggs approach maturity, a shot of HCG is given to stimulate ovulation. Either intercourse or artificial insemination (intrauterine insemination or IUI) follow the HCG “trigger” shot 24-36 hours later. Due to the cost of the medications, ultrasounds, and blood tests during a COH cycle, its cost is significantly higher than ovulation induction with oral medications.
The Ovulation Induction Process:
1. Assessment: Your fertility specialist will assess your ovulation cycle with blood tests to measure hormone levels at specific stages of your cycle; and an ultrasound to see the development of follicles in the ovaries and thickness and appearance of the uterus lining.
2. Stimulation: Your ovaries are stimulated with medications to promote the growth of follicles containing eggs. Your specialist will discuss with you the most appropriate medication or combination of medications for your situation.
3. Monitoring: Your cycle is monitored very closely with ultrasounds and/or blood tests to check the number and size of follicles developing, this is essential to reduce the risk of a multiple pregnancy.
4. Timed intercourse or artificial insemination: Near the time of ovulation your specialist will advise the most appropriate day to have sexual intercourse to maximise your chance of pregnancy or perform an intrauterine insemination where prepared sperm is inserted into the uterus.
Preferred Treatment – Ovulation Induction or IVF:
Without a doubt IVF is the most effective method of achieving a healthy, successful, singleton pregnancy. Nevertheless, ovulation induction (OI) with clomiphene, letrozole or gonadotropins followed by intrauterine insemination (IUI) remains a first line therapy for treating unexplained infertility.
Despite recommendations that OI should not be performed more than 3 or 4 cycles without achieving a pregnancy, some patients have experienced months and even years on the same ineffective OI therapy without success. Reasons given for using this less effective therapy include it being less expensive, less invasive and easier than proceeding on to more effective IVF.
In a prospective, randomized, multi-center trial of the three most common ovarian stimulation strategies (clomiphene, letrozole, gonadotropins) in 900 women with unexplained infertility – live birth rates were only 19% of cycles with letrozole, 23% of cycles treated with clomiphene, and 32% of cycles in women treated with gonadotropins.
Another advantage of IVF in young women is that often following eSET there are additional embryos suitable for vitrification (freezing) allowing these women the potential opportunity of an additional pregnancy without going through another more costly IVF cycle.