Infertility has many causes which are often discovered by fertility testing. Fertility tests examine the many processes that must occur for pregnancy to result and include:
The male must produce quality sperm in sufficient numbers to fertilize an egg. Male infertility testing primarily involves a semen analysis or a more sophisticated test the form of a semen profile.
The ovaries produce follicles, under the influence of FSH, each of which contains one egg. The follicles mature and the eggs are ovulated. Hormonal blood tests, such as measuring the FSH and LH levels, are used to help determine the cause of ovulatory disorders and can also assess egg quality and number. Ultrasound can also be used to document ovulation.
The reproductive organs must be normal and free of significant endometriosis. Laparoscopy is used to visually examine these organs and remove endometriosis.
The eggs must have the ability to fertilize and develop normally and be free of genetic defects. As women age, egg quality declines culminating in an increased incidence of infertility and miscarriage along with abnormal genetic offspring such as occurs with Down's Syndrome. Furthermore, with advancing maternal age, egg number will decline which ultimately result in menopause at an average age of fifty. Both a decline in egg number and quality can result in an elevated FSH level. A relatively new hormone called antimullerian hormone (AMH) is often used to identify those who have a decline in egg number. Fertilization can often be documented by the embryologist in an IVF cycle.
Once ovulated, the eggs must travel unimpeded into the fallopian tubes where fertilization occurs. Tubal factor infertility results when egg passage is inhibited. The hysterosalpingogram (HSG) is used to document that the tubes are open and capable of capturing an egg. Laparoscopy is also used to diagnose and possibly treat tubal disease.
Sperm must be ejaculated into the vagina and swim through the cervical mucus into the uterus. The post coital test examines sperm after exposure to the cervical mucus. Cervical factor infertility results when female antisperm antibodies damage, or kill, sperm or when the mucus is insufficient or poor quality.
The endometrium (uterine lining) must thicken and become more vascular to accept and support a developing embryo. Endometrial thickness can be measured using ultrasound. The endometrial biopsy is sometimes used to document a poorly developing endometrium.
The fertilized egg, now an embryo, must "hatch" and embed in the endometrium.
The uterus must be free of large obstructions, such as polyps and fibroidsso that the embryo can develop into a fetus. The interior of the uterus is examined using the HSG, hysteroscopy, laparoscopy, and the ultrasound.
Infertility occurs when one, or more, of these processes is inhibited.