Anovulation

Some women do not develop and release a mature egg every month as part of a woman's normal cycle in her reproductive years. We call this condition anovulation. Naturally, with no egg available for sperm, a woman cannot become pregnant. Thus, anovulation is a common reason for infertility.

Some women may have seemingly normal menstrual periods even though they are not ovulating. Most often, women who do not ovulate also do not menstruate, a disorder known as amenorrhea, or do not menstruate regularly, a condition called oligomenorrhea.

Usually the doctor can tell from discussing the details regarding previous menstrual cycles whether this is likely to be an ovulation disorder. In addition, blood testing at various times of the menstrual cycle and sometimes an ultrasound study of the ovaries can clarify whether ovulation is occurring

There are a number of causes, ranging from diet and exercise to complex disruptions in the relationships between the pituitary gland in the brain that control the ovary.

What are the causes?

• Excessive exercise and weight loss. A prolonged, strenuous program of exercise, such as running, can interfere with the ovulatory cycle by suppressing the output of hormones called gonadotropins from the a pea-size gland (pituitary gland) at the base of the brain. This woman generally has no periods and normal menstruation returns when the woman adjusts her regimen.
• Stress. Anxiety and other forms of emotional stress can take their toll on normal ovulation.
• Drugs. Certain medications such as long-acting injectable steroid contraceptives (Depo-Provera) disrupt the brain-ovarian interaction thus suppressing ovulation and preventing pregnancy. It appears that the longer the contraceptive is continued the more likely that amenorrhea will result.
• Polycystic ovarian syndrome is also a very common cause of an ovulation and infertility. When it is suspected, additional hormonal testing and ultrasound examination may be useful.