Data from: Risk factors and clinical features of ovarian pregnancy: a case-control study

Objective: To identify risk factors for ovarian pregnancy (OP) and compare clinical features between OP and tubal pregnancy (TP) patients. Design: Case-control study. Setting: University hospital. Participants: A case-control study was conducted from January 2005 to May 2014. Women diagnosed with OP were recruited as the case group (n=71), 145 women with TP and 146 intrauterine pregnancy (IUP) women were matched as controls at a ratio of 1:2:2. Women who refused interviews or provided incomplete information were excluded. Results: OP risk was lower than TP risk in women with serological evidence of Chlamydia trachomatis infection (adjusted OR1: 0.17, 95% CI: 0.06-0.52), previous adnexal surgery (adjusted OR1: 0.25, 95% CI: 0.07-0.95), and current levonorgestrel emergency contraceptive use (adjusted OR1: 0.24, 95% CI: 0.07-0.78). In vitro fertilization-embryo transfer (IVF-ET) carried a higher risk of OP (adjusted OR1: 12.18, 95% CI: 2.23-66.58) than natural conception. When Controlled by IUP women, current users of intrauterine devices (IUDs) carried a higher risk of OP than non-users of any contraceptives (adjusted OR2: 9.60, 95% CI: 1.76-42.20). β- Human chorionic gonadotropin (hCG) levels on the day of surgery were higher in OP patients than TP patients (p < 0.01). Women with OP were less likely to initially present with vaginal bleeding than those with TP (p = 0.02). Moreover, shock (p = 0.02), rupture (p < 0.01), hemoperitoneum (p < 0.01), and emergency laparotomy (p < 0.01) were more common in the OP group than the TP group. Conclusions: IVF-ET and IUD use may be risk factors for OP, and OP patients tend to have high β-hCG levels and a poor clinical outcome (shock, rupture, hemoperitoneum, and need for emergency laparotomy). Our findings may contribute to the prevention and early diagnosis of OP.