Polycystic Ovary Syndrome Health Article

Definition

Polycystic ovary syndrome (PCOS), formerly Stein-Leventhal syndrome, is a disorder in which women do not experience normal release of eggs from the ovaries, they have an abnormal production of male hormones, and their body is resistant to the effects of the hormone insulin. The disorder results in infertility, abnormal masculinization, and increased risk of developing heart disease and certain cancers.

Description

The normal function of the female reproductive system is complex, requiring the interplay of different organ systems. One set of important organs are the ovaries. The ovaries are two small structures contained in the lower abdomen, on either side of the uterus, that contain small immature eggs, called ova. Ova are stored within the ovaries in individual structures called follicles.

In a monthly cycle, a part of the brain called the pituitary gland secretes two substances into the blood stream—lutenizing hormone (LH) and follicle-stimulating hormone (FSH). As certain levels of LH and FSH build in the blood stream, the follicles of the eggs begin to swell and grow, creating cysts. Eventually, the changing levels of LH and FSH cause one of the ovarian cysts to burst open, releasing a mature egg. This process by which an egg is released from the ovary is called ovulation.

Once a mature egg is released from the ovary, it passes into the fallopian tubes, tube-like structures that are passageways to the uterus. If sperm cells from the male are present within the fallopian tubes, they will join with the egg in a process called fertilization. The fertilized egg can then pass into the uterus and implant into the thickened wall of the uterus where it can develop into a fetus. If no sperm cells are present, the mature egg goes unfertilized and is lost, along with the thickened later of the uterus, in a monthly process called menstruation.

Polycystic ovary syndrome (PCOS), first described by I. F. Stein and M. L. Leventhal in 1935, is a disorder in which normal ovulation does not occur. The term "polycystic" derives from the fact that the egg-containing cysts in the ovaries do not burst open, resulting in enlarged ovaries containing many swelled cysts. The reason for this problem in ovulation is unclear, however several abnormalities have been characterized in women with PCOS. First, there is a disturbance in the production of LH and FSH by the pituitary, leading to altered levels of the substances in the blood stream. There is also evidence that the ovaries do not respond appropriately to the FH and LSH that is present. Second, there is an

abnormal over-production of male hormones, called androgens, by the ovaries and the adrenal gland. Finally, women with PCOS are resistant to the effects of the hormone, insulin. Insulin is a hormone made in the pancreas that is responsible for transport of sugar from the blood into the cells. While these abnormalities have been well characterized, it is unclear whether they cause PCOS, or whether they are a result the disease.

Genetic profile

Women diagnosed with PCOS frequently have relatives with symptoms similar to that seen in the disorder. As a result of these observations, many scientists have proposed that genetic factors play a role in the disease. Over the past few decades, researchers have identified families in which PCOS appears to be inherited with an autosomal dominant or an X-linked pattern. However, these cases are rare and do not hold true for the majority of people with PCOS.

Current theories suggest that different genetic changes may result in PCOS or that multiple genetic factors are needed for the full manifestation of the disease. Abnormalities in several genes have been associated with PCOS, including mutations in the genes for follistatin (locus 5p14), 17-beta-hydroxysteroid dehydrogenase (locus 9p22), and a cytochrome P450 enzyme (locus 15q23-q24). Each of these genes plays a different role in the response to LH and FSH, or in the conversion of male hormones to female hormones, although their relationship to PCOS is unclear. Ongoing research is likely to identify further genetic mutations that are associated with PCOS.

Demographics

Estimates of the prevalence of PCOS in the general population have ranged from 2-20% with recent studies suggesting that 3-6% of women of reproductive age are affected by the disorder. This makes PCOS one of the most common hormone disorders in women of reproductive age.

It is unclear whether this disease is distributed uniformly among different geographical areas and ethnic groups, however, studies performed in 1999 show the prevalence of this disorder in the United States is just over 3% in African-American females and almost 5% in Caucasian females. The prevalence of PCOS in Greek women was shown to be higher, nearly 7%.