Dr. Abayomi Ajayi, Nordica Fertility Center, Lagos
While endometriosis has been reported in about 30 percent of infertile women, Polycystic Ovary Syndrome (PCOS) is the most common cause of lack of ovulation and certainly a leading cause of female infertility. Statistically, it would seem possible that some women would have both conditions and, in this environment, this is probably the case.
Both of these disorders appear to have a genetic predisposition. However, whether endometriosis is more or less common in PCOS patients and PCOS in those with endometriosis is not known. Certainly, everyone that has one of these disorders does not necessarily have the other.
If we cast our minds back, we’ll recall that the leading theory on the origin of endometriosis is a back flow of blood from the uterus through the tubes and out into the pelvis (retrograde menstruation). This theory can only partly explain the origin of endometriosis because most women have this “backward flow” each month, but endometriosis is not seen universally.
The second theory of endometriosis is that the cells lining the pelvis and ovaries are transformed into endometrial cells by some internal or external stimulus. Perhaps, blood and all the growth factors it contains is a good candidate. It can easily be seen how these two theories could work together.
So how is this related to PCOS? In one way, the point is that the PCOS patient who has very infrequent bleeding should have a decreased chance of endometriosis. In another way, oestrogen levels may be chronically elevated to a level lower than those near ovulation, but high enough to cause the endometrium to proliferate as it remains unopposed by progesterone. If endometriosis can be thought of as a fire, the fuel for the fire is oestrogen.
PCOS is associated with increased risk for endometrial hyperplasia, endometrial cancer, insulin resistance, type II diabetes, high blood pressure, high cholesterol, and heart disease. Most importantly, women with PCOS are often infertile because they don’t ovulate. In addition, some women have other factors that contribute to infertility (like a husband with a low sperm count or a uterus scarred by a previous infection), which have nothing to do with PCOS. It is such that if a woman has PCOS, it’s difficult to estimate her chances of having a baby, but there’s plenty that can be done to improve the odds.
But do all women with PCOS suffer from infertility? This is the million naira question and the answer to it depends on the criteria used to diagnose PCOS. If a main criterion is anovulation, then by definition women with PCOS would have fertility problems. It is possible to have the appearance of polycystic ovaries and be fertile, but having the syndrome usually does impact fertility adversely. It is possible that PCOS may reduce egg quality — perhaps because of abnormally high insulin levels, or because of the delayed ovulation (to which insulin resistance may contribute).
It would be appropriate to say that between 40-80 per cent of women with PCOS have a problem with fertility and the reason for this wide variation is that the condition is a complex metabolic syndrome, with multiple factors that interfere with fertility.