infertility, inability to conceive or carry a child to delivery. The term is usually limited to situations where the couple has had intercourse regularly for one year without using birth control birth control, practice of contraception for the purpose of limiting reproduction.

Methods of Birth Control

Male birth control methods include withdrawal of the male before ejaculation (the oldest contraceptive technique) and use of the condom, a
..... Click the link for more information. . The term sterility is restricted to lack of sperm production or inability to ovulate. Approximately 40% of reported cases of infertility are due to problems in the male; another 40% to problems in the female; the remaining 20% are of unknown cause or due to problems in both the male and female.

Causes

Infertility can be caused by any interruption in the usual process of fertilization, pregnancy pregnancy, period of time between fertilization of the ovum (conception) and birth , during which mammals carry their developing young in the uterus (see embryo ). The duration of pregnancy in humans is about 280 days, equal to 9 calendar months.
..... Click the link for more information. , and birth birth or labor, delivery of the fetus by the viviparous mammal. Birth is also known as parturition. Human birth normally occurs about 280 days after onset of the last menstrual period before conception.
..... Click the link for more information. , which includes ejaculation of normal amounts of healthy sperm sperm or spermatozoon (spûr'mətəzō`ən, –zō`ŏn)
..... Click the link for more information. , passage of the sperm through the cervix and into the fallopian tube fallopian tube (fəlō`pēən)
..... Click the link for more information. of the female, passage of an ovum ovum (ō`vəm), in biology, specialized plant or animal sex cell, also called the egg, or egg cell.
..... Click the link for more information. (egg) down the fallopian tube from an ovary, fertilization in the fallopian tube, implantation of the fertilized egg in a receptive uterus uterus, in most female mammals, hollow muscular organ in which the fetus develops and from which it is delivered at the end of pregnancy . The human uterus is pear-shaped and about 3 in. (7.
..... Click the link for more information. , and the ability to carry the fetus to term. In women, the most common problems are failure to ovulate and blockage of the fallopian tubes. In men, low sperm count is the most common problem.

Underlying problems include disease, such as diabetes or mumps in adult men, hormonal imbalances, endometriosis, pelvic inflammatory disease (often caused by sexually transmitted diseases sexually transmitted disease (STD) or venereal disease, term for infections acquired mainly through sexual contact. Five diseases were traditionally known as venereal diseases: gonorrhea , syphilis , and the less common granuloma inguinale,
..... Click the link for more information. , e.g., chlamydia chlamydia (kləmĭd`ēə), genus of microorganisms that cause a variety of diseases in humans and other animals.
..... Click the link for more information. ), the abuse of alcohol and other drugs, and exposure to workplace hazards or environmental toxins. Uterine irritation or infection that sometimes accompanies IUD use can also reduce fertility. Occasionally there is a chemical or immunological incompatibility between male and female. Psychological factors are difficult to evaluate because of the stressful nature of infertility itself.

The number of couples seeking treatment for infertility has increased as more of them have postponed childbearing to a later age. In women, fertility begins to decline in the mid-twenties, and continues to decline, more and more sharply, until menopause menopause (mĕn`əpôz) or climacteric
..... Click the link for more information. . Male fertility declines gradually until age forty, then declines more quickly.

Evaluation and Treatment

Evaluation includes examination of sperm, observation of basal body temperature or luteinizing hormone peaks (see gonadotropic hormone gonadotropic hormone (gō'nădətrŏp`ĭk) or gonadotropin,
..... Click the link for more information. ) in the female to determine whether ovulation is taking place, the ruling out of obstructions of the fallopian tubes or vas deferens, and blood tests that measure hormone levels. Treatment is geared to the specific problem. The first step may be treatment of underlying disease and, in men, avoidance of substances that might affect sperm count. Fertility drugs fertility drug, any of a variety of substances used to increase the possibility of conception and successful pregnancy. Different methods are used to correct or circumvent the many different functional disorders of both males and females that can interfere with
..... Click the link for more information. , some of which increase the likelihood of multiple births multiple birth, bringing forth of more than one offspring at birth. Although many smaller mammals bear several young at a time, multiple births are relatively uncommon in humans and other primates.
..... Click the link for more information. , are often prescribed. If necessary, surgical correction of blocked tubes can be attempted.

Artificial insemination artificial insemination, technique involving the artificial injection of sperm-containing semen from a male into a female to cause pregnancy. Artificial insemination is often used in animals to multiply the possible offspring of a prized animal and for the breeding
..... Click the link for more information. , in which the man's sperm or donor sperm from a sperm bank is inserted directly into the woman or a surrogate mother surrogate mother, a woman who agrees, usually by contract and for a fee, to bear a child for a couple who are childless because the wife is infertile or physically incapable of carrying a developing fetus.
..... Click the link for more information. may be attempted. Another method is in vitro fertilization in vitro fertilization (vē`trō, vĭ`trō), technique for conception of a human embryo outside the mother's body.
..... Click the link for more information. , in which an egg is taken from the mother or an egg donor and fertilized outside the body by the father's sperm. The resulting embryo is then inserted into the mother's uterus. Gamete intrafallopian transfer (GIFT) mixes the egg and sperm outside the body, then, using laparoscopic surgery (see endoscope endoscopic surgery through small incisions; such surgery is much less traumatic to the patient than traditional open surgery. Laparoscopic surgery, in which the endoscope is inserted through a small incision in the abdomen or chest, is used to correct abnormalities of the ovaries
..... Click the link for more information. ), introduces them into the fallopian tube. For men with low sperm count or sperm of low quality, a procedure called intracytoplasmic sperm injection can help by inserting a single sperm directly into an egg. If none of these measures succeeds, adoption adoption, act by which the legal relation of parent and child is created. Adoption was recognized by Roman law but not by common law . Statutes first introduced adoption into U.S. law in the mid-19th cent.
..... Click the link for more information. is sometimes considered.

Some controversy has surrounded infertility treatment. Many of the procedures are very expensive, and some question whether insurance plans should be responsible for the cost. The multiple births that sometimes occur with fertility drugs can put great strain on a family's resources. The legal rights of surrogate mothers and sperm donors are also of concern to all parties and have sometimes been resolved only after extended court cases. The wisdom of stretching the definition of "the childbearing years" has come into question as well, as methods used for treating infertility have been used to allow postmenopausal women to have children. Some are uncomfortable with the ability to choose the sex of the child or the screening of sperm or egg donors for characteristics such as height and intelligence.

See also gynecology gynecology (gīn'əkŏl`əjē), branch of medicine specializing in the disorders of the female reproductive system.
..... Click the link for more information. ; obstetrics obstetrics (ŏbstĕ`trĭks)
..... Click the link for more information. .

infertility

Inability of a couple to conceive and reproduce. It is defined as failure to conceive after one year of regular intercourse without contraception. Inability to conceive when desired can result from a defect at any of the stages required for fertility (see reproductive system). About one in every eight couples is infertile. Most cases involve the female partner, 30–40% involve the male, and 10% are caused by unknown factors. In women, causes include ovulation or hormone problems, fallopian-tube disorders, and a chemical balance that is hostile to sperm; in men, causes include impotence, low sperm count, and sperm abnormalities. Either partner can have a blockage of the pathways the sperm must travel, often treatable by surgery. Emotional factors may contribute; return of normal fertility may require only counseling. Fertility drugs can stimulate the release of eggs (often more than one, leading to multiple births). Low sperm count may be overcome by limiting intercourse to the time of ovulation, the most fertile period. If these methods are unsuccessful, couples may try artificial insemination, in vitro fertilization, or surrogate motherhood, or they may choose adoption instead.

infertility [‚in·fər′til·əd·ē]

(medicine)

Involuntary reduction in reproductive ability.