Serum β-HCG Level in Women Diagnosed as Having Retained Products Of Conception: A Prospective Cohort Study

Retained products of conception (RPOC) may occur after delivery or abortion, often necessitating operative hysteroscopy for their removal. A preoperative diagnosis of RPOC by ultrasonography is not always accurate and may lead to unnecessary surgical procedures. We sought to evaluate whether serum level of β-human chorionic gonadotropin (β-HCG) may aid in the preoperative diagnosis of RPOC.A prospective cohort study.Gynecology department in a university affiliated medical center.Women undergoing operative hysteroscopy for removal of RPOC between December 2019 and January 2021.Operative hysteroscopy for RPOC removal. Serum β-HCG levels were obtained on the day of surgery, and level ≥5.0 mIU/mL was considered positive. All operative specimens were evaluated by pathology for the presence of trophoblastic tissue.Of the 105 women recruited to the study, the operative pathology showed trophoblastic tissue in 81 cases (77.1%), and they were included in the data analysis. The β-HCG level was positive in 16 of those 81 cases (19.8%). Positive β-HCG level was significantly associated with RPOC after an abortion (surgical or medical) compared with RPOC after delivery. In addition, the mean RPOC mass was larger in the β-HCG-positive group than the β-HCG-negative group (29.1 ± 9.5 mm vs 23.8 ± 8.9 mm, respectively, p = .004), and the interval from termination of pregnancy to surgery was shorter (4.8 ± 1.7 weeks vs 7.5 ± 2.1 weeks, respectively, p <.001). Relatively high β-HCG level (352 mIU/mL and 3561 mIU/mL) were found in 2 cases in which the RPOC mass was implanted on a previous cesarean section scar.β-HCG level is noncontributory to the preoperative diagnosis of RPOC.