Infertility
What is infertility?
Infertility is the inability to become pregnant or to sustain a pregnancy that results in a live birth (miscarriages). It may be caused by any condition or disease that affects the reproductive system. Infertility is typically diagnosed after a couple has had 6 to 12 months of unprotected, well-timed intercourse without a pregnancy occurring or when a woman has been unable to maintain a pregnancy.
Fertility depends on the timing and successful interaction of many factors. Problems can occur at any point during the process of conception and, to a lesser extent, throughout the pregnancy. The female reproductive system consists of the vagina, cervix, uterus, fallopian tubes, ovaries, and vulva (the external structures). The male reproductive organs include the testicles, vas deferens, seminal vesicles, prostate gland, and the penis. Physical damage to any one of these organs may contribute to infertility. In addition, hormones produced by the hypothalamus, pituitary, and thyroid glands, as well as by the ovaries and testes, also play an important role in controlling and supporting reproduction.
In order for a successful pregnancy to occur, a woman must develop and release an egg from one of her ovaries. Women are born with a fixed number of 200,000 to 400,000 follicles that produce the eggs. At the beginning of each menstrual cycle, several follicles are stimulated by follicle-stimulating hormone (FSH) to maturity. Estrogen production also increases, peaking at day 14 of the cycle, causing the uterine lining to thicken. Luteinizing hormone (LH) increases at this time, resulting in the release of an egg (ovulation). Only one egg dominates and will be released per cycle. During a woman's reproductive years, a total of about 400 eggs are released. The egg travels through the fallopian tube and is fertilized by a man's sperm, forming an embryo. The embryo moves into the uterus and is implanted in the thickened uterine lining (the endometrium). As the embryo grows, the placenta forms, nourishing and supporting the fetus throughout the gestation period. Infertility can be associated with any one or more of the steps in this process.
An estimated 12% of American women (7.2 million) are infertile and that does not include those who have physically impaired fertility. Some of the causes of infertility are easy to identify and resolve, while others are not. They may involve one partner or both. About 65% of the time the factors are related to the woman's fertility and in 20% of the cases it is related to the man's. About 15% of the time the cause cannot be identified.
Age can play an important role especially in women, but also in men. Damaged DNA in the egg or in the sperm is thought to be related to age. In addition, hormonal imbalances may develop over time. Peak fertility in a woman occurs in her early 20s. By the time a woman reaches menopause, few if any eggs may be available or functional. As a man ages, the number of sperm decreases as does sperm motility, reducing the chances of impregnation.
Although the precise cause of infertility is sometimes not known, it typically results from several problems. Endometriosis and the effects of scaring of the fallopian tubes due to sexually transmitted diseases are common factors in infertility. The presence of other diseases or infection in either partner can be a source of the problem. Nutritional, health, lifestyle choices, and environmental factors also have an effect. Some of the most common defects reported are sperm disorders, tubal defects, ovulation problems, and cervical mucus abnormalities. Infertility testing can be complex, expensive, and time-consuming. Often, both partners are required to undergo extensive physical examinations, blood tests, evaluation of lifestyles, and/or ultrasound testing to determine the source of the problem.
