Infertility is usually defined as the inability to become pregnant after one year of vaginal intercourse without birth control.
Infertility affects about 10% of couples in their reproductive age. Approximately one-third of infertility cases can be attributed to a fertility issue with the woman; one-third with the man; and one-third either with both partners or the cause of the infertility is never found.
People shouldn't assume that they or their partners are infertile until they've tried and failed to conceive for at least 6 months if the female partner is 35 years or older, or for at least one year if the female partner is under 35 years of age. If you are still unable to get pregnant after this time, check with your doctor. Fortunately, it's not uncommon for couples to suddenly conceive a child after years of trying unsuccessfully without treatment.
Infertility in both women and men can be caused by a variety of medical conditions and problems.
Causes of infertility in women include:
- chlamydia and other sexually transmitted infections (STIs)
- damaged ovaries
- blocked fallopian tubes
- hypothyroidism (a thyroid disorder)
- endometriosis (a condition where cells from the womb lining are found outside the womb)
- polycystic ovary syndrome
- scarring in the uterus
- fibroids (benign smooth-muscle tumors of the uterus)
- congenital diseases like cystic fibrosis
- excessive exercise (leading to missed menstrual periods)
- anorexia or bulimia
- frequent changes in weight
- damage to the cervix (e.g., through an abortion or dilatation and curettage [D&C])
Infertility may seem more common these days because more people are choosing to have children later in life. But because women are less fertile as they age, women in their late 30s and early 40s naturally have a harder time conceiving, even with treatment. Although 25% to 50% of women dealing with infertility are found to have at least some traces of endometriosis upon examination, it is not known in some cases if this is the cause of the infertility.
Some women suffer repeated miscarriages, which are often due to immune problems, genetic problems, hormonal problems or occasionally, a uterus that is slightly misshapen. Occasionally, the man's sperm is unable to penetrate the woman's egg, but there is a treatment for this, too, and it requires in-vitro fertilization (IVF).
Hyperprolactinemia is another possible cause of infertility in women. This is an excess of the hormone prolactin, which normally stimulates breast milk production in women. High prolactin levels can interfere with ovulation and menstruation. Stress, marijuana, and hypothyroidism are among the factors believed to contribute to high prolactin levels. Certain prescription medications can also cause an elevated prolactin level. Rarely, it may be caused by a very small tumor in the pituitary gland of the brain that is easily treated with medication.
Women may also be concerned that having used birth control pills, vaginal rings, patches, and injections could possibly make them less fertile after they have stopped using them. There is no evidence that using birth control pills, vaginal rings, or patches increases the risk of infertility, but you may want to delay trying to get pregnant for at least one menstrual cycle after stopping these medications. This is to help you get the cycle restarted even though your periods were regular when you were using these birth control methods. But if you had irregular or infrequent periods before you began taking birth control pills or any one of these hormonal methods of birth control, your periods are likely to go back to the way they were. That is, if you were having periods every 1 to 2 months or so, the pattern will restart itself and return.
Using intrauterine devices (IUD) has also not been shown to increase the risk of infertility in women. Some women who use injection birth control methods (progesterone injections) may notice that it may take almost a year for their periods to restart and for fertility to return. Talk to your doctor or pharmacist about whether infertility may result from your method of birth control and if so, how long this time may be.
Causes of infertility in men include:
- hormone disturbance
- overheating of the testicles caused by exercise, hot water, tight clothing, excessive sitting (truck drivers) and other conditions and situations
- cancer medications and radiation therapy
- mumps after puberty
- anatomical abnormalities of the genitals such as undescended testicles
- use of some medications, such as some for high blood pressure, some antidepressants, and male hormones
- genital injury
- prostate surgery
- varicose veins in the testicles
- excessive alcohol
- intercourse problems such as premature withdrawal or poor timing with their partner's menstrual cycle
- spinal cord injury
- genetic abnormalities
- urinary tract infection
- cystic fibrosis
- illicit drug use (e.g., using cocaine, smoking marijuana)
Some men are more prone than others to infertility problems. These factors contribute to the risk of infertility:
- poor nutrition
- smoking (lowers sperm count and reduces erections)
- hot baths
- being very overweight or underweight
The environment may also affect fertility. Sperm counts are going down in industrialized countries due to unknown environmental factors.
Types of male infertility include:
- azoospermia: no sperm in the ejaculate
- oligospermia: low concentrations of sperm in the ejaculate
- asthenospermia: sperm are present but can't swim normally
- teratospermia: high proportion of abnormally-shaped sperm
- retrograde ejaculation: the tube through which sperm normally travel is blocked and sperm may end up in the bladder