About 6.1 million people are affected by infertility problems, according to the American Society for Reproductive Medicine, and of this number almost 40% are due to problems in men and another 40% due to problems in women. The remaining 20% are related to unknown causes.
In women, there is a vast length of causes of infertility. Besides a general cause of infertility, there are also other causes such as ovarian and ovulation problems, tube or peritoneal causes, hypothalamic-pituitary causes, cervical, vaginal and uterine problems, and genetic causes.
General factors would include diseases such as diabetes, thyroid or any defects and disorders of the liver and kidneys. Other than that, psychological or mental problems can also be a cause of infertility. Another common cause of infertility in women is ovarian and ovulation disorder. Women with an ovulation disorder are said to not ovulate at all or they may ovulate irregularly, compared to the normal ovulation during the 28-day cycle. Other ovarian causes would include the polycystic ovary syndrome (PCOS), ovarian neoplasm, diminished ovarian reserve, luteal dysfunction, premature menopauses, Turner syndrome, and so on. Most of these disorders prevent the release of a mature egg from the ovaries, or have hormone imbalances, or produce eggs that become damaged or have chromosomal defects. Besides that, tube or peritoneal factors also can be a cause of infertility among women. This would include Endometriosis or the uterine lining (the endometrial tissue) growing outside the uterus or it is unprepared for egg implantation, blockage of the fallopian tubes which prevents an egg from traveling to the uterus, and many more. The next cause of infertility among women is Hypothalamic-pituitary factors, which would include the common hypopituitarism, hyperprolactinemia, kallmann syndrome and other hypothalamic dysfunctions. Else than that, cervical, vaginal and uterine problems could also be a cause of infertility. Uterine problems would include problems with the structure of the uterus itself, uterine fibroids which causes congenital anomalies (birth defects) and repeated miscarriages, Asherman's syndrome, or any other uterine malformations. Vaginal Problems would include vaginal obstruction which prevents the sperms to travel to the tubes and vaginismus. Cervical problems would include the side effects of anti-sperm antibodies, insufficient cervical mucus which is needed for the sperm to travel and survive, and cervical stenosis. Another cause of infertility, although not so significant is genetic causes. This would include androgen insensitivity syndrome, fibroids, and various other conditions. External Causes All these above are internal causes of infertility. Besides these, there are also external factors which can be a cause of infertility. This would include the effects of cosmetic chemicals, alcohol, marijuana, food additives such as Monosodium Glutamate, pesticides, other anti-conceiving human hormones, coffee, cigarette or tobacco smoke, and many more.