Long episodes of regular, prolonged, abundant menstrual flows are generally agreed to increase the risk of endometriosis. Since oral oestrogen-progestogen combinations reduce and intra-uterine contraceptive devices increase menstrual flow, an effect on the risk of development of endometriosis in women utilizing these forms of contraception could be expected. Analysis of the most recent epidemiological observations shows no consensus on a possible relationship between use of cyclic oral contraceptives and endometriosis, with an increase, a decrease, and no effect on the risk of developing the disease all being reported. A lower relative risk of endometriosis in previous users of the intrauterine contraceptive device was only found in two series, most of the other data suggesting a rise in risk or no effect. Further studies on the relationship between type of contraception and endometriosis are needed to demonstrate whether the risk of development of the disease could be influenced, and whether well tolerated, relatively inexpensive, long-term treatment might be available for symptomatic patients not desiring offspring.
PIP: Epidemiologic studies on endometriosis have indicated that the various risk factors proposed have only led to less than conclusive findings. Menstrual cycle characteristics is one risk factor which seems to be significantly associated with the incidence of endometriosis. This article presents a review of epidemiological data from recently published literature. This review was conducted to clarify whether or not contraception is a risk factor for developing endometriosis. The use of oral estrogen-progestogen was the first form of contraception reviewed. Overall, there seemed to be an unclear picture presented by the seven articles reviewed. The relationship between oral contraceptive use and risk of developing endometriosis is not clearly demonstrated. The use of the IUD as another method of contraception was explored next. Most published studies suggest either no effect or an increase in risk for developing endometriosis with a history of IUD use. Further studies are needed.