Ovulation induction at a glance
- Ovulation induction is the use of hormonal medications to stimulate the production and release of eggs for fertilization in women having trouble getting pregnant.
- According to the American Society for Reproduction, 25 percent of female infertility cases are due to ovulation problems.
- Ovulation induction has become a basic infertility treatment utilized by itself and also in conjunction with other assisted reproduction treatments such as in vitro fertilization (IVF).
- Ovulation induction promotes better quantity and quality of eggs released, and thus increases pregnancy success rates.
- Ovulation induction can help women who do not ovulate at all (anovulation) —as well as those who may have subtle problems with ovulation — to produce more than one mature egg per cycle.
- Primary risks of ovulation induction are increased chance of multiple pregnancy (twins or more) and ovarian hyperstimulation syndrome (OHSS).
What is ovulation induction?
Ovulation induction involves using hormone-based fertility medications to stimulate a woman’s production and release of eggs. It has become a basic element of fertility treatments and can be employed by itself or as an element of other assisted reproductive technologies, such as intrauterine insemination (IUI), IVF and treatment of infertility due to conditions such as polycystic ovary syndrome (PCOS).
Ovulation is a major part of a normal menstrual cycle, which includes three phases. In the follicular stage, the body alters hormone levels to stimulate the follicles, resulting in one follicle only becoming dominant and creating one mature egg. The ovulatory phase releases the egg and it travels to the fallopian tubes where sperm may find and fertilize it. In the luteal stage, the follicle that produced and released the egg secretes hormones that prepare the uterus for a possible fertilized egg (an embryo).
A problem during ovulation short-circuits the cycle that can lead to pregnancy. About 25 percent of all female infertility is due to ovulation problems and ovulation induction via hormone stimulation has become an effective treatment that boosts pregnancy success rates. Ovulation problems may be failure to produce fully mature eggs or an inability to produce any eggs (anovulation).
Fertility specialists use a variety of hormone-based “fertility drugs” to treat a variety of fertility problems related to ovulation. Drugs taken orally include clomiphine citrate (Clomid), metformin (Glucophage) and letrozole, an aromatase inhibitor (AI).
Clomiphine is most often used and is effective for about 50 percent of women. It works by blocking estrogen receptors, fooling the body into producing more follicle-stimulating hormone (FSH). AIs also reduce estrogen and are particularly helpful when treating women with PCOS who are having trouble conceiving.
If these don’t work, the fertility physician may turn to injectable medications including:
- Human menopausal gonadotropin (hMG)
- Human chorionic gonadotropin (hCG)
- Gonadotropin releasing hormones (agonist or antagonists).
Women taking injectable medications will need closer monitoring in the fertility clinic.
These drugs (and others) are used on a temporary basis to overcome an ovulation problem in order to improve a woman’s chance of pregnancy. They may be used to create multiple mature eggs for use in IVF, to boost chances of success in other treatments such as IUI or to improve chances of fertilization in natural intercourse.
Diagnosing ovulation problems
Physicians may suspect ovulation problems due to unexplained infertility, meaning no cause for infertility has been identified. Other conditions or observations may also indicate ovulation problems.
Means to determine ovulation issues include:
- Tests to measure progesterone levels during the luteal phase of menstruation
- Using vaginal ultrasound to evaluate ovarian follicles
- Biopsy of endometrial tissue that evaluates hormone levels in the uterus’ lining (endometrium)
- Ovulation prediction kits that measure luteinizing hormone (LH) and body temperature.
Who should consider ovulation induction?
Women who don’t ovulate at all or who do ovulate but are not getting pregnant are good candidates for ovulation induction. The following conditions and situations can call for ovulation induction:
- Cases of anovulation, meaning the woman does not ovulate
- Irregular or infrequent ovulation (oligo ovulation), resulting in eggs not being released at the proper time
- Absence of menstrual periods (called amenorrhea) or periods that are irregular due to PCOS, abnormal pituitary hormone levels and other causes
- Hyperprolactinemia (elevated prolactin serum)
- Hypothalamic problems in which the brain’s hypothalamus doesn’t signal ovulation
- IUI procedures
- IVF procedures
- The presence of other conditions such as PCOS, endometriosis, obesity, stress, thyroid disease and eating disorders.
The fertility doctor will determine the type of fertility medication to use in ovulation induction depending on the underlying cause.
Risks of ovulation induction
Ovulation induction increases the risk of a pregnancy with twins, triplets or more. Such multiple pregnancies have health risks for mother and child including low birth weight pre-term delivery, gestational diabetes and developmental problems for the child.
Ovarian hyperstimulation syndrome (OHSS), in which the ovaries swell and become painful, can occur after ovulation induction when the drug dose is higher than the individual’s body can easily tolerate. Most cases are mild, with bloating, nausea, diarrhea and abdominal pain.
Severe cases of OHSS may involve rapid weight gain, exaggerations of the above symptoms, shortness of breath, dizziness and dark urine. Women experiencing OHSS symptoms should discuss them with their physician.
The medications themselves may produce side effects such as bloating, nausea, hot flashes, blurry vision, headaches and inflammation at injection sites.