Treatment of Infertility: Ovarian Stimulation
Ovarian stimulation is the cornerstone of many infertility treatments. By maturing more than one egg, the chance that at least one egg will be fertilized is increased. Many eggs may be needed for in vitro fertilization.
Women who do not ovulate regularly without any specific or correctable cause are good candidates for ovarian stimulation. An oral medicine called clomiphene citrate is used for this purpose. It will not work for women with a limited number of eggs. Clomiphene citrate is usually given starting between day 3 and 5 of the menstrual cycle and continuing for 5 days. Ovulation can be checked by using a urinary LH kit, basal body temperature, or a serum progesterone level in between the middle and the end of the cycle. The dose can be raised if needed.
Clomiphene citrate does raise the risk of twins, but higher multiple pregnancies rarely occur.
This type of ovarian stimulation is often paired with intrauterine insemination (IUI) in cases of male infertility. IUI, also known as artificial insemination, involves the introduction of sperm directly into the woman’s uterus via the vagina and cervix. This can be useful if there is a problem with the quantity or quality of the sperm, which can be treated beforehand.
In cases of unexplained infertility, ovarian stimulation with clomiphene along with IUI may result in a successful pregnancy. In other cases, assisted reproductive technology, or ART is needed. This is the term for any process in which both the eggs and sperm are handled in order to achieve pregnancy.
The injectable medications most commonly used to stimulate the ovaries for ART begin with a medicine similar to natural FSH, given early in a menstrual cycle. The ovaries are followed using ultrasound, and medications are given to block the normal feedback process that causes natural egg release. When a number of developing ovarian follicles can be seen, another hormone is given to further mature the follicles.
Eggs are removed from the ovaries just before they would be released naturally. This is done through the vagina, using a probe guided by ultrasound. The probe goes through the vaginal wall and then is used to delicately scoop up as many eggs as possible, which may be anywhere from 10 to 30 eggs.
Eggs will then be combined with sperm to be fertilized. The method depends on the specifics of each case (see article on ART). While the goal of all fertility treatment is a single pregnancy, having multiple embryos (which can be stored) may be helpful, because it often takes multiple attempts to actually achieve a successful pregnancy. Multiple pregnancies are possible with ovarian stimulation and IUI, as well as with ART if multiple embryos are used.
The other problem associated with ovarian stimulation syndrome is the ovarian hyperstimulation syndrome (OHSS). It rarely happens with Clomiphene and slightly more frequently with the injections given to develop many eggs. OHSS can vary in severity from mild to extreme. If too many follicles are stimulated and the level of estrogen is very high, the ovaries can swell and fluid can accumulate around the ovaries in the abdomen, and also in the chest.
The symptoms of OHSS can include abdominal bloating and slight pain, along with an increase in weight. When there is a large weight gain over a period of days, with severe abdominal swelling, pain, and shortness of breath, this is a very serious case of OHSS. OHSS must be monitored and treated. The symptoms come on after ovulation and before menstruation. If a woman becomes pregnant, the symptoms can persist over a number of weeks. Treatment at home can include resting with elevated legs and light activity, drinking plenty of suggested beverages, and avoiding heavy exercise and intercourse. In the hospital, the excess fluid can be removed from the abdomen or chest and replacement fluid can be given by vein.
Most of the time, ovarian stimulation can be done safely without complications.