Though many couples worry about unplanned pregnancies and faithfully use birth control methods to prevent pregnancy, other couples have the opposite worry. Despite months or years of trying to conceive, some women can't get pregnant.
Infertility often is defined as the inability to become pregnant after a couple has not used birth control for two years. However, women 35 years or older are encouraged to seek fertility counseling if they have not conceived after one year of trying to get pregnant.
In order for a woman to get pregnant, she must ovulate, meaning an egg must be released from one of her ovaries. This normally happens midway through the menstrual cycle, about two weeks after the day the menstrual period begins and two weeks before the next one begins.
After ovulation, the egg must travel through the fallopian tube from the ovary down toward the uterus. This transit time can take a few days. If sperm from the male joins with the egg during this time, the egg will be fertilized.
The fertilized egg must then successfully implant in the lining of the uterus for a pregnancy to begin.
Infertility can be caused by a problem with either the male or female reproductive system, or both. About 15 percent of infertility cases are due to very unusual or unexplainable causes. Male problems account for about 35 percent of infertility. The other 50 percent are due to problems with the female reproductive tract.
The quality and quantity of sperm produced by a man are factors in fertility. The best way to test for this is a semen analysis. The male simply ejaculates into a specimen cup. Then, a laboratory analyzes the sample, looking at the number of sperm, their size and shape, and their ability to swim.
If problems are found with the sperm, there are a few things men can do to improve sperm quality and quantity. Avoid binge alcohol drinking and drug use. Avoid hot tubs and wear boxers instead of briefs to keep the temperature of the testicles at a normal level. Get moderate exercise, plenty of rest and eat a healthy diet.
Some male infertility is caused by hormone abnormalities or structural problems in the reproductive system. These can sometimes be corrected by taking hormones or other medications, or by surgery.
If sperm counts are persistently low or if sperm do not travel normally, sperm can be collected and concentrated. Then, these sperm can be flushed into the female's vagina or uterus during ovulation. This is known as "artificial insemination" or "intrauterine insemination."
Female reproductive problems are generally divided into two categories: problems with ovulation and physical abnormalities that prevent pregnancy.
Ovulation problems are sometimes caused by a problem called polycystic ovary syndrome (PCOS), which I'll write more about in an upcoming column. Ovulation can be stimulated by medications in some cases. Overweight women sometimes ovulate when they lose weight.
Physical abnormalities of the female reproductive tract can cause blockages that prevent the egg and sperm from traveling normally. This can happen in the ovaries, fallopian tubes, uterus or cervix. These blockages are ofen caused by scar tissue that builds up as a result of pelvic inflammatory disease (PID) or an untreated sexually transmitted infection, such as chlamydia or gonorrhea.
Endometriosis can also be a cause of infertility. In this disease, endometrial cells that normally line the uterus attach to other parts of the pelvis, including the ovaries and fallopian tubes. More about this in a future column.
"Assisted reproductive technology" is a quickly developing field. Several methods, including in vitro fertilization ("test tube babies"), help some couples to become pregnant. The high cost of these technologies ($10,000 or more per cycle) and the increased chance of having high-risk multiple births (twins, triplets or more) are significant drawbacks.