What is ovulation induction?
Ovulation induction is the controlled stimulation of the ovaries leading to the development and eventual ovulation of usually one but sometimes up to three eggs.
Who needs it?
Any woman with ‘anovulation’ (absence of ovulation) who wants to get pregnant will need ovulation induction. The most common cause of anovulation is ‘polycystic ovary syndrome’. Another cause is excessive blood levels of a certain hormone (prolactin) that prevents ovulation. Other causes include stress, anxiety, extreme physical exertion (as with long-distance athletes), profound weight loss (greater than 15% of body weight), anorexia and serious illnesses.
Ovulation induction may also be used in some women to improve their natural hormone levels or along with certain procedures like intrauterine insemination of sperm.
How is it performed?
Couples will be assessed carefully before this treatment actually begins. Detailed histories and examinations are performed, as well as blood tests (for female hormone levels and blood count), pelvic ultrasound scans, dye tests to confirm the tubes are open, and sperm tests. The provider of the treatment will normally discuss the full details with the couple. There are different ways of achieving ovulation induction.
- Tablets – this is the most common, cheapest and simplest way of inducing ovulation. The most commonly used tablets stimulate the brain to release hormones that help the ovaries to release (ovulate) their eggs. It is given during the menstrual period (usually from the second to the sixth day) and leads to ovulation on about day 14 of the cycle. The woman’s response is usually monitored by ultrasound scans of the pelvis. Another type of tablet suppresses the abnormally high hormone levels in a condition called hyperprolactinaemia thereby leading to ovulation. These tablets are available in two forms that are given either everyday or once weekly. Pelvic ultrasound and/or measuring blood hormone levels in the latter part of the cycle are used to confirm ovulation.
- Injections – these are more effective but more expensive and dangerous than using tablets. Most units will thus reserve them for women in whom tablets fail to work. They are given as daily injections into the muscle or under the skin from about the second day of the period. Their use requires more intensive monitoring with blood hormone levels and ultrasound. Some units will give another hormone injection to ripen the eggs when they are big enough on ultrasound.
- Surgery– a form of telescopic operation on the abdomen (laparoscopy) can be performed through which small holes (3-6) are placed in one or both ovaries. This is useful in women with ‘polycystic ovary syndrome’ and can lead to ovulation and pregnancy rates that are similar to those obtained with medicines.
What else needs to be done?
Most couples will be advised to increase how often they have sex during ovulation induction treatment. Although there is no ideal pattern for this, intercourse on alternate days around the time of ovulation is generally considered sufficient. Women on tablets will generally ovulate around the middle of their cycle and ultrasound monitoring may help to pinpoint the day more accurately. Those having injections will usually be aware of the day they ovulate because of ultrasound monitoring and the hormone injection that is given to release the egg. Following surgery, the day of ovulation will need to be worked out by the doctors using ultrasound and hormone tests.
Some couples may be treated by injection of washed sperm directly into the womb around the time of ovulation (intrauterine insemination). This is useful for couples with sperm problems as well as those in whom no problems have been found in either partner. The sperm is obtained from the man by masturbation, washed in a special medium and sucked into a syringe that is attached to a small soft tube. With the woman lying on her back, the tube is passed into the womb through its neck and the sperm injected in there. The woman continues to lie down for another half-hour after the insemination. Some units will perform only one insemination about 36 hours after they induce ovulation while others will perform two or three on alternate days around the time of ovulation.
How effective is ovulation induction?
Induction of ovulation treatment is very successful in causing release of the egg from the ovaries but is much less successful in achieving pregnancy. The chances of success appear to be similar whether treatment is with tablets, injections or surgery. About 3 out of 4 women treated will ovulate successfully during each treatment cycle but only 1 in 3 of these will conceive. Combining ovulation induction with intrauterine insemination will further improve the chances of conceiving in certain couples, such as those with sperm problems or with no problems in either partner.
What problems can arise?
Problems can arise from any form of ovulation induction treatment and couples need to be aware of the common ones.
- Nausea and vomiting – ovulation induction causes the ovaries to produce higher levels of the female hormone oestrogen than the body is normally used to. This may cause nausea and vomiting in susceptible women, typically those who cannot tolerate the oral contraceptive pill because of vomiting. This problem is usually mild and short lasting.
- Swelling (bloating) of the abdomen – the combination of the bigger ovaries (because of the growing eggs they contain) and the increasing blood levels of female hormones causes swelling or bloating of the abdomen. Women who suffer from irritable bowel syndrome may experience an increased amount of this swelling.
- Discomfort in the abdomen – this may be a direct result of the increased size of the ovaries (stretching its covering skin), swelling of the abdomen, or cysts that may form in the ovaries because of the stimulation.
• Ovarian hyperstimulation syndrome –- this condition can affect up to 1 in 20 women undergoing ovulation induction. It is fortunately mostly mild, but causes pain and bloating of the tummy, vomiting, shortness of breath and tiredness. Admission to hospital may occasionally be needed for treatment. Very severe cases may become life threatening, but this is rare.
- Multiple pregnancy – the ideal of ovulation induction is the release of only one egg from the ovaries each time. This ideal is not often met and it is common for two or three eggs to be released, thus increasing the risk of multiple pregnancies. Couples need to be aware of this risk and be prepared for the possibility of twin or triplet births.