Infertility is the failure of a couple to conceive a child after trying to doso for at least one full year. In primary infertility, pregnancy has never occurred. In secondary infertility, one or both members of the couple have previously conceived, but are unable to conceive again after a full year of trying.
Currently, in the United States, about 20% of couples struggle with infertility at any given time. Infertility has increased as a problem over the last 30years.
Unlike most medical problems, infertility is an issue requiring the careful evaluation of two separate individuals, as well as an evaluation of their interactions with each other. In about 3-4% of couples, no cause for their infertility will be discovered. About 40% of the time, the root of the couple's infertility is due to a problem with the male partner; about 40% of the time, the root of the infertility is due to the female partner; and about 20% of thetime, there are fertility problems with both the man and the woman.
Male infertility can be caused problems with the sperm. A semen sample is examined under the microscope for four basic characteristics:
- The numberof sperm present in a semen sample (the sperm count). (The normal number of sperm present in one milliliter (ml) of semen is over 20 million. An individual with only 5-20 million sperm per ml of semen is considered subfertile; an individual with less than 5 million sperm per ml of semen is considered infertile.)
- Sperm motility (how well the sperm swim).
- The sperm'sphysical structure (Not all sperm within a specimen of semen will be perfectly normal. Some may be immature, and some may have abnormalities of the heador tail. A normal semen sample will contain no more than 25% abnormal forms of sperm.)
- Volume of the semen sample (An abnormal amount of semen could affect the ability of the sperm to successfully fertilize an ovum.)
Treatment of male infertility includes addressing known reversible factors first; for example, discontinuing any medication known to have an effect on spermatogenesis or ejaculation, as well as decreasing alcohol intake, and treating thyroid or other endocrine disease. Abnormally large veins in the testicles (varicoceles) can be treated surgically. Testosterone in low doses can improve sperm motility.
The first step in diagnosing a woman's fertility problems is to make sure that she is producing an ovum each month. A woman's morning body temperature isslightly higher around the time of ovulation. A woman can measure and recordher temperatures daily and a chart can be drawn to show whether or not ovulation has occurred. Luteinizing hormone (LH) is released just before ovulation.A simple urine test can be done to check if LH has been released around thetime that ovulation is expected.
Treatment of ovulatory problems depends on the cause. If a thyroid or pituitary problem is responsible, simply treating that problem can restore fertility. (The thyroid and pituitary glands release hormones that also are involved in regulating a woman's menstrual cycle.) Medication can also be used to stimulate fertility. The most commonly used of these are called Clomid and Pergonal. These drugs increase the risk of multiple births (twins, triplets, etc.).
Pelvic adhesions and endometriosis can cause infertility by preventing the sperm from reaching the egg or interfering with fertilization. However, both these conditions can be treated.
Some couple who are having trouble conceiving turn to assisted reproductive techniques, which include in vitro fertilization (IVF), gamete intrafallopiantransfer (GIFT), and zygote intrafallopian tube transfer (ZIFT). These are usually used after other techniques to treat infertility have failed.
In vitro fertilization involves the use of a drug to induce the simultaneousrelease of many eggs from the female's ovaries, which are retrieved surgically. Meanwhile, several semen samples are obtained from the male partner, and the ova and sperm are then combined in a laboratory, where several of the ovamay be fertilized. Cell division is allowed to take place up to the embryo stage. Three or four of the embryos are transferred to the female's uterus, andthe wait begins to see if any or all of them implant and result in an actualpregnancy.
GIFT involves retrieval of both multiple ova and semen, and the mechanical placement of both within the female partner's fallopian tubes, where one hopesthat fertilization will occur. ZIFT involves the same retrieval of ova and semen, and fertilization and growth in the laboratory up to the zygote stage, at which point the zygotes are placed in the fallopian tubes. Both GIFT and ZIFT seem to have higher success rates than IVF.
In general, it is believed that of all couples who undergo a complete evaluation of infertility followed by treatment, about half will ultimately have a successful pregnancy. Of those couples who do not choose to undergo evaluationor treatment, about 5% will go on to conceive after a year or more of infertility.