Serum hCG levels in the prediction of molar pregnancy below 11 weeks of gestational age.

Objective: The aim of this study was to evaluate the serum hCG level in the differential diagnosis between non-molar miscarriage and complete hydatidiform mole in<11 weeks gestation.

Methods: This was a retrospective collaborative cohort study. This study included women with gestational age<11 weeks, with ultrasound evidence of failed pregnancy and available serum hCG pre-uterine evacuation, divided into two groups: the non-molar miscarriage group and the complete hydatidiform mole group. Serum hCG levels were compared according to gestational age. Statistical analysis used a nonparametric test with a 5% significance level (p<0.05).

Results: In total, 416 patients were included, out of which 79 were included in the non-molar miscarriage group and 337 in the complete hydatidiform mole group. The calculated power of the sample was more than 80%. Data analysis showed that the 75th quartile of the median in the non-molar miscarriage group was always lower than the 25th quartile of the median in the complete hydatidiform mole group [9,721 mUI/mL/16,435 mUI/mL (6-7 weeks), 20,229 mUI/mL/64,911 mUI/mL (8-9 weeks), and 29,633 mUI/mL/126,278 mUI/mL (10-11 weeks), respectively; p<0.001].

Conclusion: Facing failed pregnancies, hCG>16,435 mUI/mL at 6-7 weeks, hCG>64,911 mUI/mL at 8-9 weeks, and hCG >126,278 mUI/mL at 10-11 weeks were most prevalent on complete hydatidiform mole diagnosis. On the contrary, hCG<30,000 mUI/mL at 10-11 weeks was most prevalent in non-molar miscarriage diagnosis.