Determining the time required to achieve negative human chorionic gonadotropin value after a nonmolar pregnancy: preliminary results.

Objective: To determine the time of human chorionic gonadotropin (hCG) regression in nonmolar gestation.

Study Design: Patients treated at our institution between June 2012 and July 2013 were selected by a deterministic sequential sampling distributed among 2 phases. Distribution of the patients included resolved cases by vaginal delivery and cesarean section in preterm and term pregnancies, ectopic, and abortion. Phase 1: serum hCG values were determined at 4, 5 and 6 weeks of obstetric resolution. Phase 2: hCG serum values were determined immediately at obstetric resolution and at 2, 3 and 4 weeks of the resolution of the cases, too.

Results: Phase 1: After the analysis of serum hCG of 63 patients at 4, 5 and 6 weeks postresolution, a negative result was corroborated in 100% of cases, in any period of the sample, with average values of 1.71, 0.55, and 0.18 mIU/mL, respectively. Phase 2 included 398 patients, with serum hCG in the first 72 hours postresolution, showing an average hCG value of 1,483.5 mIU/mL (range, 0.07-10,789), noting that 1% of cases had negative results. We then obtained hCG values at 2, 3 and 4 weeks of resolution, showing the regression in 73.4% of cases in the 2nd week, in 96.7% of patients in the 3rd week, and in all cases in the 4th week.

Conclusion: The regression of hCG after nonmolar pregnancy does not exceed 3 weeks.