Some cancer treatments, such as a hysterectomy, cause permanent infertility in women at any age. Total body irradiation causes very high rates of infertility, but a few young women have had babies afterward.

Another cause of infertility in women is premature ovarian failure, which is when menopause occurs before a woman is 40. Premature ovarian failure happens when both ovaries are surgically removed, and may also occur if the ovaries are damaged by chemotherapy. High-dose chemotherapy is more destructive than lower doses. Chemotherapy with alkylating agents, such as cyclophosphamide, is very toxic and can directly damage the ovaries. Radiation to the ovaries also can be damaging, resulting in temporary or permanent menopause.

Younger women and those who had lower doses of chemotherapy or radiation therapy are more likely to regain menstrual periods, though they may not occur regularly. Women over 35 are less likely to recover their fertility. This may be because a woman in her 30s has fewer eggs in reserve, so a larger percentage of eggs are destroyed. However, even young women are at risk for early infertility and menopause because eggs in the ovaries may be damaged or killed by cancer treatment.

Cancer treatment can cause temporary or permanent infertility in men, too. Men begin producing sperm cells at puberty and continue to be fertile the rest of their lives. To produce permanent infertility, a cancer treatment must eliminate all stem cells in the testicles that produce new, mature sperm cells. This can happen if both testicles are removed, if the testicles get a high dose of radiation, or if very high doses of alkylating chemotherapy drugs are given. Men with testicular cancer, who are typically young, are likely to be infertile before they are diagnosed with cancer, but about half recover good fertility despite having a testicle removed and undergoing chemotherapy.

There are several ways to try to preserve fertility in women, but most remain experimental, with unknown success rates. Some options are not appropriate for certain patients, depending on the type of cancer.

Eggs are removed from the patient and fertilized in a test tube with the sperm of a partner or donor. The resulting embryos are then frozen and stored. It takes about two weeks from the start of a woman's menstrual cycle to get eggs to use for in vitro fertilization; waiting may be a problem with a fast-growing cancer like acute leukemia. Also, the hormones given so that more than one of a woman's eggs will ripen may stimulate breast cancer cells to grow, so researchers are trying to use different hormone combinations to make hormonal stimulation safer. Another option would be to simply harvest the one egg that ripens in a natural menstrual cycle, but the chance that the egg will fertilize, survive freezing and produce a live birth when transferred to the woman's uterus is less than 10%.

Some women opt to have the eggs frozen unfertilized, particularly if they are not in a committed relationship. Later, the eggs can be thawed and in vitro fertilization attempted. Egg-freezing remains experimental and has resulted in fewer than 200 live births around the world.

Some women have parts of their ovaries removed surgically and frozen before cancer treatment. Although some centers are banking ovarian tissue before cancer treatment, this technique is still experimental and has resulted in only a few pregnancies worldwide.

For women receiving chemotherapy, one option may be to take a hormone that puts the ovaries into temporary menopause during treatment. However, many infertility specialists doubt that the hormones truly prevent the chemotherapy from damaging the ovaries. The hormone shots are expensive, and it is possible that they could have some impact on the success of chemotherapy.

For women receiving radiation treatment, it may be possible to move the ovaries out of the radiation area surgically. Sometimes they can be relocated at the sides of the pelvis, out of the radiation target field. There is a 50% chance that women will resume menstruating after this procedure.

Other options for becoming a mother after cancer treatment include using donor embryos or eggs, having a surrogate (where another woman carries the child), or adoption.

Fertility preservation is much easier, cheaper and more effective for most men. It simply involves collecting a sample of semen and freezing it. Sperm must be banked before any chemotherapy or pelvic radiation therapy begins in order to avoid storing damaged sperm. The sperm can be thawed later and used for intrauterine insemination or in vitro fertilization.

Many young men diagnosed with cancer have poor sperm quality because of the illness, recent anesthesia or stress. Even if a man has only a few live sperm in his semen, they can be used for in vitro fertilization to provide a good chance of pregnancy. In this situation, when the sample is thawed, the healthiest sperm are captured and injected into the woman's harvested eggs using a robotic microscope in the laboratory.

Insurance generally does not cover the cost of the sperm banking, and storing one ejaculate for five years averages around $500. Some sperm banks have special payment plans for cancer patients. For men who no longer ejaculate semen but would like to bank sperm, a urologist may be able to collect sperm from the storage areas above the testicles or even from tissue inside the testicles with outpatient surgery.

For some people, fertility does return after cancer treatment. However, it may take a long time.

For women, the return of menstruation may or may not signal fertility, but getting blood tests for hormones and other tests performed by an infertility specialist can give a better answer.

Women who have had chemotherapy or have had radiation treatment to the pelvic or abdominal area should consult an obstetrician before trying to get pregnant, to make sure that their heart, lungs and uterus are healthy enough to avoid pregnancy complications. For example, when a girl or young woman has radiation that includes the uterus, it is important to know whether the uterus is normal in size and can expand enough during pregnancy.

Men often have low sperm counts or motility (movement) at the time their cancer is diagnosed, but this may improve after treatment. Sperm quality may rise for several years following cancer treatment, depending on the drugs used, the doses and each person's individual recovery. Even though men may produce sperm, the number and motility may not be enough to conceive without some medical help. A semen analysis, in which a man's semen is examined under a microscope, can indicate whether a pregnancy is likely through intercourse, or what type of infertility treatment will be needed. Because each person's situation is different, it is important to talk to your doctor before trying to start a pregnancy.

If you wish to have children after cancer treatment, discuss the issue with your doctor as soon as possible. You also may want to talk to a counselor familiar with cancer and fertility to prepare yourself for challenges and decisions.

• Is there anything that can be done before starting my cancer treatment to increase the likelihood that I will be able to have children?
• I am interested in freezing eggs or embryos. Is this an option for me? Could you please give me more information?
• I am interested in sperm banking. Is this an option for me? Could you please give me more information?
• I stopped having my period, but could I still get pregnant? Should I be using birth control?
• For how long will we need to prevent pregnancy during cancer treatment? Are condoms the best method for us?
• My partner is pregnant. Is there any special reason to avoid sex during my cancer treatment?
• Will my cancer treatment cause me to be infertile? Do you expect this to be temporary or permanent?
• Now that my cancer treatment has ended, I would like to have children. Is it OK for us to try to become pregnant?
• We have been trying to get pregnant without success. Should we talk to an infertility specialist?