Threatened abortion: Prediction of viability based on signs and symptoms

Objective: To examine the relationship between signs and symptoms associate d with threatened abortion and viability of the pregnancy. Design: A prospective observational study Setting: A university teaching hospital Participants: One thousand consecutive women presenting with a threatened a bortion. Intervention: A structured history and an examination were performed as ini tial clinical assessment. These were followed by transvaginal sonography to determine the status of the pregnancy. Main outcomes: The relationship between individual signs and symptoms and t he status of the pregnancy was determined. Logistic regression was performe d to determine which signs or symptoms were independent predictors of spont aneous abortion. Results: A history of having passed a tissue mass, the presence of products of conception in the vagina and an open cervix were the only sign or sympt om associated with a greater than 90% chance that the pregnancy was non-via ble. Logistic regression of signs and symptoms at presentation indicated that ma ternal age greater than 35 years, a history of passing clots vaginally, vag inal bleeding similar to normal menstruation, increasing vaginal bleeding a nd discrepancy of 4 or more weeks between the uterine size on examination a nd that which would have been expected by menstrual dates were significant predictors of nonviable pregnancy. A history of vomiting was predictive of a viable pregnancy. Conclusion: The clinical assessment of threatened abortion is unreliable in most cases and should be superseded by ready access to sonographic assessm ent.