Demographic, behavioral, and contraceptive practices have been evaluated in cross-sectional studies as risk factors for PID (Table 43–1). Among demographic risk factors, age younger than 19 years,16–18 lower socioeconomic group,16,19 non-Caucasian race,16,17,20 lack of married status,16,21 and less education17,22 have been associated with increased risk of PID. Behavioral risk factors overlap with those for acquiring STIs. High-risk behaviors include early sexual debut,16,18,19,23 having multiple sexual partners,23–25 and having a current or past STI.16,18–21,26 A history of PID is reported by some19 but not all17,18 authors as an independent risk factor for recurrence. Use of substances like alcohol,18,27 tobacco,17,19,22,28 and cocaine17 may also increase PID risk. Additionally, engaging in sex during menses19,24 and douching29–31 are behaviors that remain controversially associated with PID.
Contraceptive practices also alter the risk of PID. Lack of any contraception is associated with 7.6-fold increased PID risk,24 while inconsistent condom use increases risk by three-fold.17 Intrauterine devices (IUDs) have traditionally been associated with the development of PID,32,33 but recent data demonstrate that the risk is limited to the first 20 days following IUD insertion34 and possibly if the IUD is inserted during concurrent cervicitis.35 IUD placement otherwise, perhaps even in populations with high prevalence of STIs, appears safe.32 Whether hormonal contraception alters PID risk remains unresolved. Both combination oral and progesterone-only injectable forms are associated with increased risk of Chlamydia trachomatis cervicitis.36–38 Oral contraceptive use by a large cohort of women resulted in a nonsignificant reduction in PID risk.36 Use of depot medroxyprogesterone significantly decreased PID risk by 60% among this cohort,36 but was associated with increased risk in a different study.19 Interestingly, case-control data showed that women with subclinical PID diagnosed by endometrial biopsy were 4.3 times more likely to be on oral contraceptives than women with recognized PID,39 whereas use of oral contraception by a large cohort of women with acute PID was associated with a nonsignificant trend toward a reduced pain score.18 These data indicate that the decreased risk associated with hormonal contraceptives may be attributable to a decrease in presenting symptomatology, rather than to an absolute reduction in PID incidence.