26 CT can lead to ectopic pregnancy by causing tubal abnormalities and dysfunction www.selleckchem.com/products/brefeldin-a.html (eg, abnormal cilia activity or tubal contractility), which is the main reason for TP,27 whereas the tubal factor does not seem to be a crucial factor for OP.28 Therefore, it was not surprising that CT was associated more strongly with TP than with OP. These findings also explained why previous adnexal surgery was not a risk factor for OP but was for TP. LNG, a synthetic progestogen, is a widely used EC.29 Research has suggested that it acts by delaying the luteinising

hormone surge and interfering with ovulation,30 thereby preventing pregnancy. However, several cases of ectopic pregnancy following LNG-EC failure have been reported.31 32 In the present

study, 4 OPs, 25 TPs and 8 IUPs were observed among 37 women with LNG-EC failure. Compared with non-users of contraceptives, women who used LNG-EC did not show an increased risk of OP compared to TP. This finding may be associated with the fact that an elevated progesterone concentration could theoretically impair cilia motility in the fallopian tube and lead to a predisposition to tubal implantation in women using progestin-only pills.33 An important part of this study was that clinical features were compared between OP and TP, which, to the best of our knowledge, has not been done previously. We found a significant difference between these groups with respect to vaginal bleeding. OP patients were less likely to present vaginal bleeding than TP patients. This finding may be associated with the fact that because of the increased vascularity of ovarian tissue in OP patients, the endometrium is well

maintained with high β-hCG levels in these patients, unlike in the case of TP patients. Many patients consider bleeding the principal sign of an abnormal pregnancy and it is often their strongest motivation to seek medical attention. Without bleeding, patients may be reassured by amenorrhoea as a sign of a normal IUP,34 which might delay the diagnosis and treatment of OP. Therefore, even in patients who do not present with vaginal Anacetrapib bleeding, strong suspicion of pregnancy is prudent in order to avoid missing a case of OP. Our study clearly found higher β-hCG levels on the day of surgery in OP patients than those in TP patients. This may be attributed to the proper embryonic development resulting from the increased vascularity of ovarian tissue in the former. The incidence of rupture was significantly higher in the OP group (56.34%) than the TP group (5.52%).