CHAPTER 249
Infertility
Infertility is the inability of a couple to achieve a pregnancy after repeated intercourse without contraception for 1 year.
Frequent intercourse without birth control usually results in pregnancy:
For 50% of couples within 3 months
For 75% within 6 months
For 90% within 1 year
To maximize the chance of pregnancy, couples should have frequent intercourse for the few days when egg release (ovulation) is most likely—usually in the middle of the menstrual cycle, which is about halfway between the first day of two periods. Women who have regular periods can estimate when ovulation occurs by measuring their temperature at rest (basal body temperature) each day before they get out of bed. A decrease suggests that ovulation is about to occur. An increase of 0.9° F (0.5° C) or more suggests ovulation has just occurred. Or women may use home ovulation predictor kits, which test urine or saliva. Use of caffeine and tobacco, which can impair fertility in women, is discouraged. Even with these measures, about one in five couples in the United States do not conceive for at least a year and are thus considered infertile.
The cause of infertility may be due to problems in the man, the woman, or both:
Problems with sperm (in 35% of couples)
Problems with ovulation (in 20%)
Problems with the fallopian tubes in the pelvis (in 30%)
Problems with mucus in the cervix (in 5% or fewer)
Unidentified factors (in 10%)
Thus, the diagnosis of infertility problems requires a thorough assessment of both partners.
Age is a factor, especially for women. As women age, becoming pregnant becomes more difficult and the risk of complications during pregnancy increases. Also, women, particularly after age 35, have a limited time to resolve infertility problems before menopause.
Of the couples who have not conceived after a year of trying, more than 60% conceive eventually, with or without treatment. The goals of treatment are to treat the cause of infertility if possible, to make conception more likely, and to reduce the time needed to conceive.
Even when no cause of infertility can be identified, the couple may still be treated. In such cases, the woman may be given drugs that stimulate several eggs to mature and be released—so-called fertility drugs (see page 1589). Examples are clomiphene and human gonadotropins. A woman’s chances of becoming pregnant are about 10 to 15% with each month of treatment. Alternatively, an artificial insemination technique that selects only the most active sperm may be tried.
While a couple is being treated for infertility, one or both partners may experience frustration, emotional stress, feelings of inadequacy, and guilt. They may alternate between hope and despair. Feeling isolated and unable to communicate, they may become angry at or resentful toward each other, family members, friends, or the doctor. The emotional stress can lead to fatigue, anxiety, sleep or eating disturbances, and an inability to concentrate. In addition, the financial burden and time commitment involved in diagnosis and treatment can cause marital strife.
These problems can be lessened if both partners are involved in and are given information about the treatment process (including how long it takes), regardless of which one has the diagnosed problem. Knowing what the chances of success are, as well as realizing that treatment may not be successful and cannot continue indefinitely, can help a couple cope with the stress. Information about when to end treatment, when to seek a second opinion, and when to consider adoption is also helpful. Ideally, couples should ask for this information before treatment is begun. Counseling and psychologic support, including support groups such as RESOLVE and the American Fertility Association, can help.
Problems With Sperm
Sperm may be too few in number, move too slowly, or be structurally abnormal, or their passage out of the body may be blocked or disrupted.
An increase in the testes’ temperature, certain disorders, injuries, and some drugs and toxins can cause problems with sperm.
Semen is analyzed, and sometimes genetic tests are done.
Clomiphene, a fertility drug, may increase the number of sperm, but assisted reproductive techniques may be needed.
To be fertile, a man must be able to deliver an adequate quantity of normal sperm to a woman’s vagina, and sperm must be able to fertilize the egg. Conditions that interfere with this process can make a man less fertile.
WHAT CAUSES INFERTILITY IN MEN?
| CAUSE | EXAMPLES |
| Reduced sperm production | |
| Increased temperature of the testes | Excessive heat Disorders that cause a prolonged fever |
| Hormonal disorders | Adrenal gland disorders (this gland produces testosterone and other hormones) Hyperprolactinemia Hypogonadism Hypothalamic disorders (this part of the brain controls the pituitary gland, which controls testosterone production) Hypothyroidism Pituitary gland disorders |
| Genetic disorders | Klinefelter’s syndrome Other disorders that cause an abnormality in the sex chromosomes |
| Disorders of the testes | Infections Injury to the testes Mumps that affects the testes (mumps orchitis) Shrinking of the testes (as can occur when excess alcohol is regularly consumed) Undescended testes (testes that remain in the abdomen rather than move to the scrotum) Varicose veins in the testes (varicocele) |
| Drugs | Anabolic steroids Alcohol, when consumed in large amounts Androgens (such as testosterone) Aspirin when taken for a long time Chlorambucil (a chemotherapy drug) Cimetidine (used to treat stomach ulcers) Colchicine (used to treat gout) Corticosteroids taken by mouth (such as prednisone) Cotrimoxazole (an antibiotic) Cyclophosphamide (a chemotherapy drug) Drugs used to treat malaria Estrogens taken to treat prostate cancer Gonadotropin-releasing hormone (GnRH) analogs (used to treat prostate cancer) Marijuana Medroxyprogesterone (a synthetic female hormone) Methotrexate (a drug that suppresses the immune system) Monoamine oxidase inhibitors (MAOIs—a type of antidepressant) Nicotine Nitrofurantoin (an antibiotic) Opioids (narcotics) Spironolactone (a diuretic) Sulfasalazine (an antibiotic) |
| Exposure to industrial or environmental toxins | Heavy metals, such as lead Pesticides (which can have effects similar to those of female hormones or decrease the effects of male hormones) |
| Absence of sperm in semen | |
| Disruption of the sperm’s passage out of the body | Missing epididymides (which provide the space and environment for sperm to mature), usually in men with cystic fibrosis Blocked or missing vasa deferentia (tubes from the epididymides to the ejaculatory ducts), usually in men with cystic fibrosis Missing seminal vesicles (which provide nourishment for sperm) Blockage of both ejaculatory ducts |
| Retrograde ejaculation (semen travels back into the bladder rather than out of the penis) | Diabetes Nervous system dysfunction Pelvic surgery, such as prostate removal Removal of lymph nodes in the area behind the abdomen (as may be done to treat Hodgkin lymphoma) |
Causes
Conditions that increase the temperature of the testes (where sperm are produced) can greatly reduce the number of sperm and the vigor of sperm movement and can increase the number of abnormal sperm. For example, taking a hot bath before sexual intercourse can negatively affect sperm. Some disorders of the testes, such as undescended testes and varicose veins, also increase the temperature of these organs. Effects of excessive or prolonged heat can last up to 3 months.
Certain hormonal or genetic disorders may interfere with sperm production, as can other disorders.
Exposure to industrial or environmental toxins and use of certain drugs can reduce sperm production. Taking anabolic steroids (such as testosterone) lowers production of the pituitary gland hormones that stimulate sperm production.
Some disorders result in the complete absence of sperm (azoospermia) in semen. They include serious disorders of the testes and blocked or missing vasa deferentia, missing seminal vesicles, and blockage of both ejaculatory ducts. The same genetic abnormality that causes cystic fibrosis can cause azoospermia, often by preventing both vasa deferentia from forming.
Azoospermia can also occur if semen, which contains the sperm, moves in the wrong direction (into the bladder instead of down the penis). This disorder is called retrograde ejaculation (see page 1487).
Diagnosis
Doctors ask the man about his medical history and do a physical examination to try to identify the cause. Doctors ask about past disorders and surgery, use of drugs, and possible exposure to toxins. They check for physical abnormalities, such as undescended testes, and for signs of hormonal or genetic disorders that can cause infertility. Levels of hormones (including testosterone) may be measured in the blood.
A semen analysis, the main screening procedure for male infertility, is needed. For this procedure, men are often asked not to ejaculate for 2 to 3 days before the analysis. The reason is to make sure the semen contains as many sperm as possible. Then they are asked to ejaculate by masturbation into a clean glass jar, preferably at the laboratory site. For men who have difficulty producing a semen sample this way, special condoms that have no lubricants or chemicals toxic to sperm can be used to collect semen during intercourse.
The volume of the semen sample is measured. Whether the color, consistency, thickness, and chemical composition of semen are normal is determined. The sperm are counted. A low sperm count may mean that fertility is reduced, but not always. Sperm are also examined under a microscope to determine whether they are abnormal in shape, size, or movement.
If the semen sample is abnormal, the analysis may be repeated because samples from the same man normally vary greatly. Two or three samples, obtained at least 1 week apart, provide more accurate results than a single sample. If the semen still seems to be abnormal, the doctor tries to identify the cause. If there are too few sperm, genetic testing is done. Also, urine may be checked for sperm after ejaculation to determine whether retrograde ejaculation is occurring.
Did You Know…
Taking a hot bath before sexual intercourse makes conception less likely.
Using anabolic steroids can decrease sperm production.
Other tests can be done to evaluate sperm function and quality if routine tests of both partners do not explain infertility. These tests may
Detect antibodies to sperm
Determine whether sperm membranes are intact
Determine the sperm’s ability to bind to an egg and penetrate it
Sometimes a biopsy of the testes is done to obtain more detailed information about sperm production and the function of the testes.
Treatment
If possible, the disorder causing the problem is treated. For example, varicoceles can be treated with surgery. Sometimes fertility improves as a result.
Clomiphene, a drug used to trigger (induce) ovulation in women, may be used to try to increase sperm counts in men. However, whether clomiphene improves the sperm’s ability to move or reduces the number of abnormal sperm is unclear. It has not been proved to increase fertility.
For men who have a low sperm count with normal-appearing motile sperm, artificial insemination may slightly increase their partner’s chances of pregnancy. This technique uses the first portion of the ejaculated semen, which has the greatest concentration of sperm. A technique that selects only the most active sperm (washed sperm) is somewhat more successful. With washed semen, pregnancy usually occurs by the sixth attempt if it is going to occur. In vitro fertilization, often with intracytoplasmic sperm injection (the injection of one sperm into one egg), and gamete intrafallopian tube transfer (GIFT) are much more complex and costly procedures. They are successful in treating many types of male infertility.
For men who produce no sperm, inseminating the woman with sperm from another man (a donor) may be considered. Because of the danger of contracting sexually transmitted diseases, including infection with human immunodeficiency virus (HIV), fresh semen samples from donors are no longer used. Risk of disease transmission is minimized by freezing donor sperm for 6 months or more, then retesting donors for infection. If their test results remain negative, the sample is thawed and used.
Before artificial insemination or another technique is used, the partner of a man who has fertility problems may be treated with human gonadotropins to stimulate several eggs to mature and be released (see page 1589). This approach may make pregnancy more likely.
Problems With Ovulation
The ovaries do not release an egg each month (see page 1494).
Ovulation problems can result from dysfunction of the part of the brain and the glands that control ovulation or dysfunction of the ovaries.
Women can determine whether ovulation is occurring and estimate when it occurs by measuring body temperature or using home predictor kits.
Doctors use ultrasonography or blood or urine tests to evaluate ovulation problems.
Drugs, usually clomiphene, can often stimulate ovulation, but pregnancy does not always follow.
In women, a common cause of infertility is an ovulation problem.
Causes
Ovulation problems result when one part of the system that controls reproductive function malfunctions. This system includes the hypothalamus (an area of the brain), pituitary gland, ovaries, and other glands, such as the adrenal glands and thyroid gland. For example,
The hypothalamus may not secrete gonadotropin-releasing hormone, which stimulates the pituitary gland to produce the hormones that stimulate the ovaries to trigger ovulation (luteinizing hormone and follicle-stimulating hormone).
The pituitary gland may produce too little luteinizing hormone or follicle-stimulating hormone.
The ovaries may produce too little estrogen.
The pituitary gland may produce too much prolactin, a hormone that stimulates milk production. High levels of prolactin (hyperprolactinemia) may result in low levels of the hormones that trigger ovulation. Prolactin levels may be high because of a pituitary gland tumor (prolactinoma), which is almost always noncancerous.
Other glands may malfunction. For example, the adrenal glands may overproduce male hormones (such as testosterone), or the thyroid glands can overproduce or underproduce thyroid hormones, which help keep the pituitary gland and ovaries in balance.
Ovulation problems may be due to many disorders. One of the most common causes is polycystic ovary syndrome, which is characterized by excess weight and excess production of male hormones by the ovaries. Other causes include diabetes and obesity. Problems may also result from excessive exercise, certain drugs (such as estrogens and progestins and antidepressants), weight loss, or psychologic stress. Sometimes the cause is early menopause—when the supply of eggs runs out early.
An ovulation problem is often the cause of infertility in women who have irregular periods or no periods (amenorrhea—see page 1524). An ovulation problem is sometimes the cause of infertility in women who have regular menstrual periods but do not have premenstrual symptoms, such as breast tenderness, lower abdominal swelling, and mood changes.
Diagnosis
To determine if or when ovulation is occurring, doctors may ask a woman to take her temperature at rest (basal body temperature) each day. If possible, she should use a basal body temperature thermometer (which is highly accurate) or, if it is unavailable, a mercury thermometer. Electronic thermometers are the least accurate. Usually, the best time is immediately after awakening. A decrease in basal body temperature suggests that ovulation is about to occur. An increase of more than 0.9° F (0.5° C) in temperature usually indicates that ovulation has just occurred. However, this method is inconvenient for many women and is not reliable or precise. At best, it predicts ovulation only within 2 days. A more accurate method is an ovulation predictor kit for use at home. This kit detects an increase in luteinizing hormone in the urine 24 to 36 hours before ovulation. Urine is tested on several consecutive days.
Doctors can accurately determine whether and when ovulation occurs. Methods include ultrasonography and measurement of the level of progesterone in the blood or saliva or the level of one of its by-products in the urine. A marked increase in these levels indicates that ovulation has occurred.
Doctors may do other tests to check for disorders that can cause ovulation problems. For example, they may measure testosterone levels in the blood to check for polycystic ovary syndrome.
Treatment
A drug to trigger ovulation, such as clomiphene or human gonadotropins, may be used. The particular drug is selected based on the specific problem. If the cause of infertility is early menopause, neither clomiphene nor human gonadotropins can stimulate ovulation.
Clomiphene Plus Medroxyprogesterone: If ovulation has not occurred for a long time, clomiphene with medroxyprogesterone is usually preferred. First, the woman takes medroxyprogesterone, usually by mouth, to trigger menstrual-like bleeding. This drug is taken for 5 to 10 days. A few days after bleeding begins, she takes clomiphene by mouth for 5 days. Usually, she ovulates 5 to 12 days after clomiphene is stopped and has a menstrual period 14 to 16 days after ovulation. Clomiphene is not effective for all causes of ovulation problems. It is most effective when the cause is polycystic ovary syndrome.
If a woman does not have a period after treatment with clomiphene, she takes a pregnancy test. If she is not pregnant, the treatment cycle is repeated. A higher dose of clomiphene is used in each cycle until ovulation occurs or the maximum dose is reached. When the dose that triggers ovulation is determined, the woman takes that dose for at least three or four more treatment cycles. Most women who become pregnant do so by the fourth cycle in which ovulation occurs. Although about 75 to 80% of women treated with clomiphene ovulate, only about 40 to 50% become pregnant. About 5% of pregnancies in women treated with clomiphene involve more than one fetus, primarily twins.
Side effects of clomiphene include hot flashes, abdominal bloating, breast tenderness, nausea, vision problems, and headaches. Fewer than 1% of women treated with clomiphene develop ovarian hyperstimulation syndrome. In this syndrome, the ovaries enlarge greatly and a large amount of fluid moves out the bloodstream into the abdomen. This syndrome may be life threatening. To try to prevent it, doctors prescribe the lowest effective dose of clomiphene, and if the ovaries enlarge, they stop the drug.
Human Gonadotropins: If a woman does not ovulate or become pregnant during treatment with clomiphene, hormonal therapy with human gonadotropins, injected into a muscle or under the skin, can be tried. Human gonadotropins stimulate the follicles of the ovaries to mature. Follicles are fluid-filled cavities, each of which contains an egg (see page 1493). Ultrasonography can detect when the follicles are mature. Then, the woman is given an injection of a different hormone, human chorionic gonadotropin, to trigger ovulation. When human gonadotropins are used appropriately, more than 95% of women treated with them ovulate, but only 50 to 75% become pregnant. About 10 to 30% of pregnancies in women treated with human gonadotropins involve more than one fetus, primarily twins.
Human gonadotropins can have severe side effects, so doctors closely monitor the woman during treatment. About 10 to 20% of women treated with human gonadotropins develop ovarian hyperstimulation syndrome. If hyperstimulation occurs, doctors may not give the woman human chorionic gonadotropin to trigger ovulation. Human gonadotropins are also expensive.
If the cause of infertility is early menopause, neither clomiphene nor human gonadotropins can stimulate ovulation.
Other Drugs: If the hypothalamus does not secrete gonadotropin-releasing hormone, a synthetic version of this hormone (called gonadorelin acetate), given intravenously, may be useful. This drug, like the natural hormone, stimulates the pituitary gland to produce the hormones that trigger ovulation. The risk of ovarian hyperstimulation is low with this treatment, so close monitoring is not needed. However, this drug is not available in the United States.
When the cause of infertility is high levels of the hormone prolactin, the best drug is one that acts like dopamine, called a dopamine agonist, such as bromocriptine or cabergoline. (Dopamine is a chemical messenger that generally inhibits the production of prolactin.)
Problems With the Fallopian Tubes
The fallopian tube may be blocked or damaged, preventing the egg from moving from the ovary to the uterus to be implanted.
To identify the problem, doctors may use x-rays taken after a radiopaque dye is injected through the cervix or may directly view the organs through a viewing tube (laparoscope) inserted through an incision just below the navel.
The fallopian tubes can sometimes be repaired, but in vitro fertilization is usually recommended.
Sometimes the fallopian tubes are blocked or damaged so that the egg cannot move from the ovary to the uterus. Causes include previous disorders and situations, such as the following:
Pelvic infections (such as pelvic inflammatory disease)
Use of an intrauterine device if it causes a pelvic infection (which is rare)
A ruptured appendix
Surgery in the pelvis or lower abdomen
A mislocated (ectopic) pregnancy in the fallopian tubes Current conditions may also block the tubes:
Birth defects of the uterus and fallopian tubes
Endometriosis
Fibroids in the uterus
Bands of scar tissue between normally unconnected structures (adhesions) in the uterus or pelvis
Diagnosis
Procedures used to determine whether the fallopian tubes are blocked include the following:
Hysterosalpingography: X-rays are taken after a radiopaque dye is injected through the cervix. The dye outlines the interior of the uterus and fallopian tubes. This procedure is done a few days after a woman’s menstrual period ends. This procedure can detect structural disorders that can block the fallopian tubes. However, in about 15% of cases, hysterosalpingography indicates that the fallopian tubes are blocked when they are not—called a false-positive result. After hysterosalpingography, fertility appears to be slightly improved even if the results are normal, possibly because the procedure temporarily widens (dilates) the tubes or clears the tubes of mucus. In such cases, doctors may wait to see if a woman becomes pregnant after this procedure before additional tests of fallopian tube function are done.
Sonohysterography: A salt (saline) solution is injected into the interior of the uterus through the cervix during ultrasonography so that the interior is distended and abnormalities can be seen. If the solution flows into the fallopian tubes, the tubes are not blocked. This procedure is quick and does not require an anesthetic. It is considered safer than hysterosalpingography because it does not require radiation or injection of a dye. However, it is not as accurate.
If an abnormality within the uterus is detected, doctors examine the uterus with a viewing tube called a hysteroscope, which is inserted through the cervix into the uterus. If adhesions, a polyp, or a small fibroid is detected, instruments inserted through the hysteroscope may be used to dislodge or remove the abnormal tissue, increasing the chances that the woman will become pregnant.
If evidence suggests that the fallopian tubes are blocked or that a woman may have endometriosis, a small viewing tube called a laparoscope is inserted in the pelvic cavity through a small incision just below the navel. Usually, a general anesthetic is used. This procedure enables doctors to directly view the uterus, fallopian tubes, and ovaries. Instruments inserted through the laparoscope may also be used to dislodge or remove abnormal tissue in the pelvis.
Treatment
Treatment depends on the cause. Abnormal tissue is often dislodged or removed during diagnosis (using hysteroscopy or laparoscopy).
Surgery can be done to repair a fallopian tube damaged by an ectopic pregnancy or an infection. However, after such surgery, the chances of a normal pregnancy are small, and those of an ectopic pregnancy are higher than usual. Consequently, in vitro fertilization is often recommended instead.
Problems With Mucus in the Cervix
If mucus in the cervix is abnormal, it may prevent sperm from entering the uterus or may promote the destruction of sperm.
Normally, mucus in the cervix (the lower part of the uterus that opens into the vagina) is thick and impenetrable to sperm until just before release of an egg (ovulation). Then, just before ovulation, the mucus becomes clear and elastic (because the level of the hormone estrogen increases). As a result, sperm can move through the mucus into the uterus to the fallopian tubes, where fertilization can take place.
Abnormal mucus may do the following:
Not change at ovulation (usually because of an infection), making pregnancy unlikely
Allow bacteria in the vagina, usually those that cause infection in the cervix (cervicitis), to enter the uterus, sometimes resulting in the destruction of sperm
Contain antibodies to sperm, which kill sperm before they can reach the egg
Usually, abnormal mucus causes infertility only if the abnormal mucus causes chronic cervicitis or if the cervix has been narrowed by treatment for a precancerous abnormality of the cervix (cervical dysplasia).
Did You Know…
Mucus in the cervix changes consistency to allow sperm to enter the uterus.
Diagnosis
Doctors examine women to see whether the cervix is narrow and to check for infection.
Tests to determine whether the mucus promotes sperm destruction are rarely used because these tests do not accurately predict the chances of pregnancy.
Treatment
Treatment may include placing semen directly in the uterus to bypass the mucus (intrauterine insemination). Drugs to thin the mucus, such as guaifenesin, may be used. However, there is no proof that either treatment increases the chances of pregnancy.
Problems With Eggs
The number of eggs may be low, or the quality may be poor.
The number and quality of eggs (ovarian reserve) may begin to decrease at age 30 or even earlier. They decrease rapidly after age 40. But age is not the only cause. Abnormalities in the ovaries can also cause such a decrease.
Diagnosis and Treatment
Doctors may evaluate the following women for problems with eggs:
Those who are 35 or older
Those who have had ovarian surgery
Those who have responded poorly to fertility drugs (such as gonadotropins) that stimulate several eggs to mature and be released
Doctors can usually confirm the diagnosis by measuring levels of follicle-stimulating hormone (which triggers ovulation) and estrogen in the blood at a certain time during the menstrual cycle. Sometimes doctors give women clomiphene, a fertility drug, before measuring these levels.
If women are older than 42 or if the number or quality of eggs is decreased, using eggs from another woman (donor) may be the only way to achieve pregnancy.
Unidentified Factors
Unidentified factors are considered the explanation for infertility when semen in the man and ovulation and fallopian tubes in the woman are normal.
When no explanation for infertility is identified, the following approach is used:
Women are given a fertility drug (clomiphene), which stimulates several eggs to mature and be released, and human chorionic gonadotropin (hCG), which triggers ovulation, for up to three menstrual cycles. This treatment may result in more than one fetus.
Semen is placed directly in the uterus to bypass the mucus (intrauterine insemination) within 2 days after ovulation is triggered by treatment with fertility drugs.
If pregnancy does not result, other assisted reproductive techniques, such as in vitro fertilization, are tried.
If clomiphene plus hCG is unsuccessful, women are sometimes given human gonadotropins (see page 1589) before assisted reproductive techniques are tried. Women have the same chance of pregnancy (about 65%) whether in vitro fertilization is done immediately after unsuccessful treatment with clomiphene plus hCG or whether human gonadotropins are given next, before in vitro fertilization is tried. However, women become pregnant more quickly if in vitro fertilization is done immediately after unsuccessful treatment with clomiphene plus hCG.
Assisted Reproductive Techniques
Assisted reproductive techniques involve manipulating sperm and eggs in a culture dish (in vitro) with the goal of producing an embryo.
If treatment has not resulted in pregnancy after four to six menstrual cycles, assisted reproductive techniques, such as in vitro fertilization or gamete intrafallopian tube transfer, may be considered. These techniques are more successful in women under age 35. In the United States, more than 43% of cycles of in vitro fertilization in women under 35 resulted in pregnancy, and almost 87% of the pregnancies ended in live births. In contrast, only about 18% of attempts in women aged 41 to 42 resulted in pregnancy, and only about 60% of the pregnancies resulted in live births. For women over 42, using eggs from another woman (donor) is recommended.
Assisted reproductive techniques may result in more than one fetus but are less likely to do so than fertility drugs. If the risk of genetic abnormalities is high, the embryo can often be tested before it is implanted in the woman’s uterus. This testing is called preimplantation genetic diagnosis.
Did You Know…
An embryo can be tested for genetic abnormalities before it is implanted in the woman.
In Vitro (Test Tube) Fertilization (IVF): This technique is used when infertility is due to certain problems with sperm, problems with the fallopian tubes, or abnormal mucus in the cervix and when women have endometriosis, as well as when the cause is unidentified. The technique involves the following:
Stimulating the ovaries: Typically, a woman’s ovaries are stimulated with clomiphene, human gonadotropins, or both. A gonadotropin-releasing hormone agonist or antagonist is often given to prevent ovulation from occurring until after several eggs have matured. As a result, many eggs usually mature. Then, human chorionic gonadotropin is given to trigger ovulation.
Retrieving released eggs: Guided by ultrasonography, a doctor inserts a needle through the woman’s vagina into the ovary and removes several eggs from the follicles. Sometimes the eggs are removed through a small tube (laparoscope) inserted through a small incision just below the navel.
Fertilizing the eggs: The eggs are placed in a culture dish and fertilized with sperm selected as the most active.
Growing the resulting embryos in a laboratory: After sperm are added, the eggs are allowed to grow for about 2 to 5 days.
Implanting the embryos in the woman’s uterus: One or a few of the resulting embryos are transferred from the culture dish into the woman’s uterus through the vagina. The number of embryos implanted is determined by the woman’s age and likelihood of response to treatment.
Additional embryos can be frozen in liquid nitrogen to be used later if pregnancy does not occur. Despite the implantation of several embryos, the chances of producing one full-term baby are only about 18 to 25% each time eggs are placed in the uterus. The chances of having a baby with in vitro fertilization depend on many factors, but the woman’s age may be most important.
The greatest risk is having more than one fetus (multiple pregnancy). A multiple pregnancy can cause serious complications in the mother and the newborns: The mother may have excessive bleeding, the fetuses may die, or the babies may have a low birth weight. Because of these complications, doctors now transfer fewer embryos to the uterus at one time.
Intracytoplasmic Sperm Injection: This technique may be used when other techniques are likely to be unsuccessful or when the problem with sperm is severe. It resembles in vitro fertilization except that only one sperm is injected into only one egg.
Gamete Intrafallopian Tube Transfer (GIFT): This technique can be used if the fallopian tubes are functioning normally. Eggs and selected active sperm are obtained as for in vitro fertilization, but the eggs are not fertilized with sperm in the laboratory. Instead, the eggs and sperm are transferred to the far end of the woman’s fallopian tube through a small incision in the abdomen (using a laparoscope) or through the vagina (guided by ultrasonography), so that the egg can be fertilized in the fallopian tube. Thus, this technique is more invasive than in vitro fertilization.
Other Techniques: These techniques include the following:
Transfer of a more mature embryo (blastocyst transfer)
Use of eggs from another woman (donor)
Transfer of frozen embryos to a surrogate mother
These techniques raise moral and ethical issues, including questions about the disposal of stored embryos (especially in cases of death or divorce), legal parentage if a surrogate mother is involved, and selective reduction of the number of implanted embryos (similar to abortion) when more than three develop.