Infertility may be the result of a number of different problems, most of which can be corrected. In general, the causes of infertility in men & women can be divided into seven categories. These categories and their incidence specifically in couples seeking treatment are:
A common misconception is that infertility is primarily a woman’s “problem”. In fact, male factor infertility affects the same number of couples as female factor infertility. An additional 25% of couples who seek treatment have more than one factor or condition affecting their ability to reproduce.
In recent years, age-related infertility has become an increasingly common problem. Both men and women are most fertile at age 24. Fertility rates begin to trend downward thereafter and decline significantly after age 35.
Life style choices and environmental factors can also have an impact on fertility. Caffeine intake, smoking, substance abuse and the use of herbal medicine have all been shown to decrease fertility rates. You can learn about how these factors impact fertility and the things you need to know before you get pregnant on this web site.
A common misconception is that infertility is only a woman’s problem. In fact, for almost 50% of infertile couples, the cause is related to the male partner, either alone or with a coinciding female factor. This is why we encourage couples to approach infertility together. Advances in reproductive technology have resulted in several effective treatments to assist couples that have been diagnosed with male infertility.
Some of the causes of male infertility include:
How do we identify male infertility? A semen sample is analyzed for the volume of semen, the concentration of sperm, the percent of actively moving sperm and the numbers of normal shaped sperm. An abnormality of one or more of these parameters suggests a problem with the sperm. The greater the abnormality detected in the semen analysis, the greater the likelihood that the sperm are a factor in the couple’s infertility.
Although a semen analysis is the most commonly used method to assess sperm, it is important to realize that the analysis is not very precise or predictive. There are many men with abnormal semen analyses that have normal fertility. Still, an abnormal semen analysis requires further evaluation, often in conjunction with an urologist.
A semen analysis cannot fully predict the capability of the sperm to fertilize an egg due a myriad of other potential factors, some of which maybe present in the female partner. When male factor infertility is identified, we recommends a complete infertility evaluation of the woman be performed.
Approximately 10 – 30% of all couples undergoing infertility treatment are diagnosed with “unexplained infertility.” This means that the causes of their infertility are subtle and therefore undetectable using the tests available to fertility specialists. The prognosis for conceiving for couples that are diagnosed with unexplained infertility is usually good.
Couples who are diagnosed with unexplained infertility are encouraged to seek treatment immediately. These couples usually respond well to an appropriate treatment regimen. Success rates for couples with unexplained infertility working with fertility medication and intrauterine inseminations (IUI) are between 15 – 20%. Success rates are even higher with assisted reproductive technology such as in vitro fertilization (IVF).
Fertilization occurs where the sperm and egg meet in the mid-portion of the fallopian tube. The fertilized egg (embryo) then travels down the tube for 5-7 days before arriving in the uterine cavity. Problems with fertility may arise if the fallopian tubes have been damaged and are unable to function properly.
Tubal problems are found in approximately 20–25% of women who are having difficulty getting pregnant. These problems can be diagnosed using hysterosalpingogram (HSG), an x-ray dye examination, or a laparoscopy. Most women with tubal problems benefit from in vitro fertilization (IVF) and are successful in delivering a healthy baby.
The most common conditions that interfere with the health of the fallopian tubes are:
Tubal (ectopic) pregnancy can occur when scars from a past infection partially obstruct the tubes. When the tubes are blocked, the sperm and egg may successfully fertilize, but the resulting embryo will not pass into the uterus. This can lead to a painful and possibly life threatening pregnancy.
Ectopic pregnancy and infection can also damage the thin hairs that line the fallopian tubes that assist in bringing the sperm and egg together. If the hairs have been harmed, fertilization may not occur.
A ruptured appendix may cause intra-abdominal scarring that may need to be surgically repaired.
The typical woman has menstrual cycles that occur every 21 to 35 days. These cycles are the result of an integrated system between several organs – the hypothalamus, the pituitary gland and the ovary. When these organs function properly, it leads to the normal cyclic release of an egg (ovulation) during menstruation. Women with menstrual cycles at intervals of greater than 35 days are considered to have infrequent ovulation, or oligo-ovulation. Other women do not ovulate at all which is called anovulation.
Menstrual abnormalities are often best treated with oral contraceptives or cyclic progesterone. Metabolic abnormalities are best treated by a combination of diet and, moderate exercise. Additional complications can arise from tumors, but in many cases these are also very treatable.
Due to the complexity of these conditions, Boston IVF strongly recommends that women suffering from ovulation disorders, or who suspect they might be, contact one of our experts as soon as possible.
There are many causes of oligoovulation and anovulation, some of which include:
Polycystic ovary syndrome (PCOS) is a metabolic disorder and is the most common cause of anovulatory infertility. This syndrome may also include obesity (50% of women with PCOS are obese), various hormonal problems and high levels of blood insulin.
Infertility is present in the majority of women with this syndrome, and they have a higher risk of miscarriage. Their reproductive organs are normal, but the hormonal balance between them is disrupted. The condition is diagnosed by symptoms (irregular menstrual cycles, obesity, acne and facial hair), which can vary, and a blood test.
Higher than normal levels of insulin are believed to stimulate the ovary to produce excess testosterone, altering the level of other hormones and impairing ovulation. The body continues to try to ovulate monthly, creating growing numbers of immature follicles on the ovary – the basis for the name “polycystic ovary”.
Weight loss, birth control pills and fertility medications can be used to treat PCOS and achieve pregnancy.
Peripheral Endocrine Disorders
Increased ovarian production of estrogen eliminates the normal feedback to the hypothalamus and pituitary, and may lead to anovulation. This condition may be a result of adrenal disorders, obesity, or specific tumors, and can be treated with medication.
Disorders Of The Hypothalamus Hypothalamic Pituitary Dysfunction
Tumors in the hypothalamus, head trauma or radiation may damage the hypothalamus and impair its function, or they may transect the pituitary stalk and cause resulting hypothalamic hypopituitarism. This condition is very treatable.
Functional Hypothalamic Amenorrhea
Strenuous exercise has been demonstrated to have a detrimental impact on reproductive function. The incidence is higher in high-intensity runners and ballet dancers. It is believed that menstrual function requires a level of at least 22% body fat for normal menses to occur. Extreme exercise may lead to complete disruption of the hypothalamic pituitary ovarian axis.
Stress and eating disorders may also cause anovulation by disrupting the hypothalamus. With psychological and nutritional rehabilitation, this inhibition is released and ovulatory function resumes.
Pituitary Gland Disorders Pituitary Adenomas And Hyperprolactinemia
Pituitary tumors (adenomas) occur frequently. Prolactin producing tumors are the most common and account for 70% of all adenomas which affect estrogen production. Medical therapy is common for managing this condition. Surgical treatment is reserved for tumors that are unresponsive to medical therapy.
Age Related Reasons
Advanced age is now the leading cause of infertility. However, it is one of the most easily treated forms of infertility. Couples over 35 are advised to seek the help of a fertility specialist after 6 months of unsuccessful, unprotected, well-timed intercourse. Successful treatments are available for both men and women.
For women, age-related infertility is the result of declining “ovarian reserve”. Women are born with a finite number of eggs that begin to be depleted from birth. Monthly ovulation further reduces the ovarian reserve. By the time a woman is between 50 and 60, she will have naturally depleted all of her eggs (also known as menopause).
Aging can also impact the quality of a woman’s eggs. Present from the time of birth, eggs are some of the oldest living cells in the female body. As a result, they may not be viable at a later stage in a woman’s life.
Men are capable of producing sperm continually throughout their life. However, age can affect a man’s testicular function and cause a reduction in hormonal levels. Lower levels of testosterone can lead to diminished interest in sex and lower levels of sperm production. The quality of a man’s sperm may also be impaired over time. All couples having difficulty getting pregnant should have a semen analysis performed to rule out male factor infertility.
Endometriosis And Pelvic Pain
The uterus contains a cavity lined by tissue called endometrium. Endometriosis is a condition where this tissue grows outside of the uterus. Typical sites for endometriosis include the ovaries, ligaments behind the uterus and the pelvic cavity.
It is important to note that most women with endometriosis have no symptoms whatsoever. Infertility is often their first symptom of this disorder. Most women with endometriosis conceive readily without treatment.
Other women may experience painful periods, painful intercourse and non-cyclic abdominal pain. If the endometriosis is near the bladder or bowel, one may have discomfort or bleeding while going to the bathroom. Normal hormonal changes associated with the menstrual cycle can cause endometriosis to become irritated and/or bleed. Such bleeding can lead to the development of scar tissue which may lead to difficulty conceiving.
There are numerous theories as to the cause of endometriosis. The most widely accepted is that the flow of blood during menses brings viable endometrial cells to the ovaries and the rest of the pelvis. Other theories include immunologic factors, transformation of cells into endometriosis cells, and vascular and lymphatic spread.
Laparoscopy, a minor outpatient surgical procedure, is the most common treatment for endometriosis.
Women with moderate disease can expect a pregnancy success of approximately 60%. Women with severe disease can expect a pregnancy success of approximately 35% following surgical treatment.
Cervical & Uterine Conditions
Abnormalities of the cervix affect fertility. One of the most common causes of cervical factor infertility is prior surgery on the cervix, such as a cone biopsy, or laser therapy of the cervix to treat pre-cancerous cervical cancer. The cervix can also be congenitally abnormal as with in-utero diethylstilbestrol (DES) exposure. Treatments for cervical factor infertility can vary. Some of the main options include IUI, IVF and GIFT.
Abnormalities to the shape of the uterus can also impact fertility. Some of these include: