Age- Reduced Ovarian Reserve

Egg quality and fertilization capacity are directly correlated with female age. By the age of 43, most women have entered the perimenopause and can no longer become pregnant without IVF using donor eggs.

Under hormonal stimulation, the eggs develop inside the follicles and when they are mature, they are ovulated. As eggs age, they loose their capacity to fertilize and develop. The number of eggs in the ovary reduces with age. This reduction in egg numbers and their reduced ability to fertilize is referred to as "reduced ovarian reserves". Reduced ovarian reserve can occur at any age and some women experience perimenopause. Perimenopause can produce menopausal symptoms years prior to the actual menopause.

One of the first signs of diminishing ovarian reserve is an elevated day 3 FSH measurement (>12). FSH levels continue to rise and Inhibin B levels tend to fall as the egg numbers fall and they loose their capacity to fertilize. The Clomid Challenge test may be ordered to help determine if IVF will be successful.

Ovulatory Disease

In order for successful conception to occur, the monthly ovulatory cycles must be regular and culminate in the release of healthy eggs. All of the ovulatory cycle events are controlled by complex hormonal interactions.

The hypothalamus, a small gland at the base of the brain, serves as the "thermostat" regulating various hormone levels. The hypothalamus signals the pituitary to produce FSH during the first days of the ovulatory cycle. FSH stimulates follicle recruitment and supports the eggs as they mature. As the follicles (and eggs) develop, they begin to produce estrogen, which helps prepare the endometrium to receive a developing embryo. The hypothalamus monitors estrogen levels and regulates FSH production accordingly. Once the eggs mature the hypothalamus signals the pituitary to release a surge of LH causing ovulation.

Many conditions lead to ovulatory disorders and include PCOS, reduced ovarian reserve, diseases of the hypothalamus, pituitary, or thyroid glands. Ovulation can also be affected by environment factors such as excessive exercise or stress.

Polycystic Ovarian Disease (PCOS)

PCOS is a common cause of failed ovulation and infertility. PCOS patients usually have high insulin levels leading to the overproduction of androgens and lack of ovulation. Please see our discussion of this important condition.

Tubal Disease

The eggs must travel from the ovaries through the fallopian tubes to the distal end of the tube, where fertilization occurs. Blocked fallopian tubes due to endometriosis, infection, scarring, sterilization, or other factors are a common cause of infertility. Tubal disease can sometimes be corrected by surgery but in general cycle success rates are higher with IVF. The advantage of surgery to reconnect the tubes is that there is not limit to the number of cycle attempts. The number of IVF attempts is often limited by cost.

Cervical Factor

Sperm must be ejaculated into the vagina and "swim" though the cervical mucus through the cervix to the uterus. Cervical factor infertility can result if the cervical mucus is too thick to support the sperm. Sometimes a woman's immune system may produce antibodies to sperm. When this occurs sperm are destroyed in the same manner as viruses and bacteria. IUI is an effective treatment because the sperm are placed directly into the uterus thus avoiding the cervical mucus.

Uterine Factor

The uterus must be normally shaped and free of obstructions such as large fibroids or polyps. Some women are born with congenital abnormalities of the uterus, as is the case with a bicornuate uterus. Some abnormalities can be corrected with surgery. The uterus can also be damaged by severe pelvic infections. If the uterus is severely damaged, the only treatment option may be to use a surrogate mother.

Endometriosis

Endometriosis is a common cause of infertility and occurs when cells that normally line the uterus (endometrium) attach to other internal organs. Endometriosis can cause damage to the fallopian tubes, uterus, ovaries and other organs. Also, this abnormally placed endometrial tissue secretes many immunoactive agents that prevent fertilization of the egg.

Endometrial tissue depends upon estrogen for growth during the ovulatory cycle. One means to treat endometriosis is to reduce estrogen levels with drugs like Lupron. In most case, endometrial lesions will be removed during laparoscopic surgery.

A disease affecting any one (or more) of the above events can cause infertility.

Male Factor Infertility

In the male, infertility may be genetic, congenital (born without testes), due to trauma, continuous exposure to heat or chemical toxins, bacterial or viral diseases, and others. Procedures, such as ICSI, can help sub-fertile and infertile men father children. See the Section on Male Infertility