ObjectiveEctopic pregnancy continues to be a leading cause of maternal morbidity and of reduced childbearing potential among women of reproductive age. Because of tubal rupture, it is still the main cause of pregnancy-related death during the first trimester. The purpose of our study was to evaluate factors that may predispose a woman to rupture of a tubal ectopic pregnancy.MethodsIn this retrospective study of 693 ectopic pregnancies from three McGill University teaching hospitals, we compared risk factors, preoperative ultrasound, and serum hCG levels between cases with ruptured and unruptured tubal ectopic pregnancy.ResultsThe age and the number of pregnancies among the two groups of women were similar. The gestational age of women with an unruptured tube was 6.9 ± 1.9 weeks, and of those with a ruptured tube, the gestational age was 7.2 ± 2.2 weeks. Tubal rupture was encountered more often in women with at least one child than in childless women. History of ectopic pregnancy was found in 35% of women with an unruptured tubal pregnancy and in 26% of those with a ruptured tube. Serum hCG levels at the time of treatment were not significantly different among the two groups of women. Eleven percent of women with a ruptured tube had serum β-hCG levels of less than 100 IU/L.ConclusionTubal rupture is encountered more often in women with no history of ectopic pregnancy and in those with at least one child. This suggests that ectopic pregnancy is less suspected in these women. Tubal rupture is encountered less often in ampullary pregnancy and in small ectopic pregnancies. There is no correlation between serum β-hCG levels and tubal rupture, and rupture can occur even when serum β-hCG levels are very low.