Human chorionic gonadotropin level as a predictor of trophoblastic infiltration into the tubal wall in ectopic pregnancy: a blinded study

Objective: To determine the relationship between gestational age, tubal ultrasonographic diameter, and serum hCG levels and different stages of trophoblastic infiltration of the tubal wall in ectopic pregnancy. Design: Blinded prospective study. Setting: University-based clinic in Italy. Patient(s): Thirty-seven consecutive patients with an ampullary ectopic pregnancy. Intervention(s): Laparoscopic salpingectomy. Main Outcome Measure(s): Gestational age, diameter of the tubal mass as determined by transvaginal ultrasonography, and hCG level on the day of surgery. Ectopic pregnancy was classified according to the depth of trophoblastic infiltration: trophoblast limited to the tubal mucosa (stage 1), extension to the tubal muscularis (stage II), or complete tubal wall infiltration up to the serosa discontinued by trophoblastic cells (stage III). Result(s): Fifteen patients (40.5%) had stage I tubal infiltration, 14 (37.8%) had stage II infiltration, and 8 (21.6%) had stage III infiltration. Gestational age and diameter of the tube did not differ among the three groups. The median hCG level was 1,710.5 mIU/mL (range, 113-5,635 mIU/mL) for patients with stage I infiltration, 4,690.0 mIU/mL (range, 150-21,531 mIU/mL) for patients with stage II infiltration, and 15,700.0 mIU/mL (range, 13,809-21,650 mIU/mL) for patients with stage III infiltration. All the patients with hCG levels > 6,000 mIU/mL had stage II or III invasion. Conclusion(s): These findings may explain why the conservative treatment of ectopic pregnancy is less successful in patients with high hCG levels than in patients with low levels. Use of radical procedures may be justified in the former group.