Serial changes in serum hCG
Finally, we examined the transition in serum hCG levels in cases with conservative management. Of the 16 cases in which serum hCG was measured, the median time from delivery to serum hCG level below the measurable threshold was 67 (23-113) days. Next, we investigated the changes in serum hCG levels in cases in which serum hCG was examined at least twice before falling below the measurable threshold. In seven cases that delivered after 34 weeks of gestation but did not undergo UAE, the median half-life of serum hCG was 4.7 (2.3-7.5) days (Figure 4A).
Serum hCG levels decreased rapidly after UAE in three patients (Figure 4B). Among the cases who delivered before 20 weeks of gestation and did not undergo UAE, the median half-life of serum hCG was 7.4 (3.8-39.1) days (Figure 4C, 4D). None of the cases delivered after 34 weeks of gestation had a hCG half-life of > 10 days, whereas three cases delivered before 20 weeks of gestation had a half-life of >10 days (Figure 4D).