The inability to produce offspring, which may result from a problem in either the male or the female reproductive system, or, in many cases, from a combination of problems in both. The main cause of male infertility is a lack of healthy sperm. In azoospermia, no sperm are produced; in oligospermia only a few sperm are produced. In some cases, sperm are produced but are malformed or short-lived. The underlying cause of these problems may be blockage of the spermatic tubes or damage to the spermatic ducts, usually due to a sexually transmitted infection. Abnormal development of the testes due to an endocrine disorder (see hypogonadism) or damage to the testes by orchitis may also cause defective sperm. Smoking, toxins, or various drugs can lower the sperm count. Other causes are disorders affecting ejaculation (see ejaculation, disorders of). Rarely, male infertility is due to a chromosomal abnormality, such as Klinefelter’s syndrome, or a genetic disease, such as cystic fibrosis. The most common cause of female infertility is failure to ovulate. Other causes are blocked, damaged or absent fallopian tubes; disorders of the uterus, such as fibroids and endometriosis; problems with fertilization, or implantation in the uterus (see implantation, egg). Infertility also occurs if the woman’s cervical mucus provides antibodies that kill or immobilize her partner’s sperm. Rarely, a chromosomal abnormality, such as Turner’s syndrome, is the cause of a woman’s infertility. Investigations to discover the cause of a woman’s infertility may include blood and urine tests, to check that ovulation is occurring, and laparoscopy to determine whether or not an abnormality is present. The initial investigation for male infertility is seminal fluid analysis. Treatment of male infertility is limited. The only option for azoospermia is adoption of children or artificial insemination by a donor. If the sperm count is low, artificial insemination by the male partner may be tried. In some cases of male infertility due to a hormonal imbalance, drugs such as clomifene or gonadotrophin hormone therapy may prove useful. Failure of the woman to ovulate requires ovarian stimulation with a drug such as clomifene, either with or without a gonadotrophin hormone. Microsurgery can sometimes repair damage to the fallopian tubes. If surgery is unsuccessful, in vitro fertilization (IVF) is the only option. Uterine abnormalities or disorders, such as fibroids, may require treatment. In some cases, provided the woman has normal fallopian tubes, gamete intrafallopian transfer (GIFT) or zygote intrafallopian transfer (ZIFT) may be carried out.


Online Medical Dictionary: Your essential reference to over 5000 medical terms.