Contraception and the etiology of pelvic inflammatory disease: new perspectives

Abstract

The dramatic increase in use of contraception worldwide makes it imperative to understand the effects of contraceptives on the health of women using them. In this article, we review the literature on the relationships of modern nonsurgical contraception with pelvic inflammatory disease. Subsequently, we identify areas where further research is needed to better define the risks and benefits of these contraceptive methods in various settings. From our review, two new conclusions emerge. First, our reanalysis of published data on the risk of PID associated with intrauterine device (IUD) use compared with no contraceptive use shows, with one exception, less risk than the previous comparisons to all non-IUD use. Second, and probably most importantly, the studies, when taken together, strongly imply that oral contraceptives have a protective effect against PID. Only one study of 11 is equivocal on this point.

PIP: A review of reported studies on IUD and PID (pelvic inflammatory disease) generally points to an increased risk of 150% to 400% for IUD users compared to nonusers of contraceptives. Comparison with all non-IUD contraception shows a 3 to 5-fold increase in risk. The difference in relative risk may not be statistically significant, but it is consistent and may be real. The protective effect of oral contraceptives may explain the difference in risk as in most studies, risk with oral contraceptives use is about half compared with nonuse of any contraception. In a control population with a high proportion of oral contraceptive use, overall risk of PID is lowered, whereas relative risk of IUD is elevated. Apparent relationship of contraception to PID can be explained by many factors such as misdiagnoses of PID, and age and parity of women. Other contraceptive methods (eg. condoms and diaphragms with spermicidal chemicals) are also associated with lower PID risks than IUD and are associated with decreased prevalence of gonorrhea. International implications of the PID-IUD relationship in the developing world are briefly discussed.