Risk factors for recurrent ectopic pregnancy - a retrospective case-control study.

BACKGROUND: To investigate risk factors and clinical characteristics of recurrent ectopic pregnancies. The study specifically aims to compare demographic data, laboratory findings, and reproductive histories between patients with single and recurrent episodes to identify predictors for secondary prevention. METHODS: From December 2007 to December 2011, 199 women with single ectopic pregnancy and 51 women with recurrent ectopic pregnancy were identified from our hospital records. The information collected for each woman included age, smoking status, recurrent time, signs and symptoms, laboratory findings, and treatment parameters. RESULTS: The recurrence rate was 20.4%. Mean age was comparable between groups (30.2 ± 4.9 vs. 30.5 ± 5.7 years, P = 0.800). Gravidity was significantly higher in the recurrent group (3.4 ± 1.8 vs. 2.8 ± 1.5, P = 0.028), and gravida ≥ 4 was more frequent among recurrent cases (43.1 vs. 28.1%, P = 0.030). A history of abortion was significantly more common in the recurrent group (45.1 vs. 18.1%, P = 0.001), corresponding to an approximately fourfold increased risk (OR 3.9, 95% CI 1.7-7.9). Serum b-hCG levels were significantly higher in recurrent cases (5,135.8 ± 5,230 vs. 3,153.0 ± 5,643 mIU/mL, P = 0.040). b-hCG > 4,000 mIU/mL was more frequent in the recurrent group (33.3 vs. 18.1%, P = 0.017), whereas b-hCG levels between 2,001-4,000 mIU/mL were less frequent (7.8 vs. 23.1%, P = 0.015). Smoking status, intrauterine device use, prior cesarean section, ultrasonographic localization, rupture rates, treatment modalities, and complication rates did not significantly differ between groups (P > 0.05). In a multivariate analysis, only a history of abortion remained an independent predictor of recurrent ectopic pregnancy (OR 3.01, 95% CI 1.499-6.043, P = 0.002). CONCLUSION: When ectopic pregnancy is diagnosed early and appropriate treatment modality is selected, morbidity, mortality, radical intervention rate, and treatment costs are significantly reduced. Therefore, women of reproductive age should be informed about ectopic pregnancy symptoms by clinicians to increase community awareness. Moreover, for successful secondary prevention, identification of modifiable risk factors for recurrent ectopic pregnancy is important.