(149) Associations between H48/H0 β-hCG ratio in the fourth gestation week and pregnancy outcomes：A retrospective analysis

Objective:
Does an H48/H0 hCG ratio of pregnancy in the fourth gestation week associate with pregnancy outcomes in pregnancy loss patients? we aimed to investigate the correlations between hCG ratio and pregnancy outcomes in patients with a history of pregnancy loss.

Study Design:
This is a retrospective cohort study, the receiver operator curves were plotted to determine the optimal cut-off for the pregnancy outcomes. The odds ratio was also calculated through univariable and multivariable analyses, with continuous variables categorized into binary categories based on the cut-off value.

Results:
In total, 279 women ended with live birth and 79 with no live birth. A lower H48/H0 ratio of hCG in the fourth gestation week was an independent risk factor for no live birth (p＜0.01) and preterm birth (p=0.03). The optimal value for predicting no live birth of H48/H0 is 1.85 (AUC=0.717). For early pregnancy loss, the optimal value of H48/H0 is 1.85 (AUC=0.711), and for biochemical pregnancy loss, it is 1.55 (AUC=0.953). Compared to the live birth group, patients with a H48/H0 ratio < 1.85 exhibited a significantly higher risk of no live birth (OR: 9.54, 95% CI: 5.16-17.63). Similarly, individuals with a H48/H0 ratio < 1.55 faced an elevated risk of biochemical pregnancy loss (OR:603.0, 95% CI: 61.08-5953.14). A H48/H0 ratio (< 2.56) was associated with a tendency towards an increased risk of preterm birth (OR: 1.85, 95%CI:0.74-4.65).These odds ratio remained consistent even after adjusted by age, BMI, previous losses, initial hCG(H0), E2 and P. 

Conclusion:
 Our study revealed that the H48/H0 ratio of hCG in the fourth gestation week of pregnancy might be correlated with both no live birth and preterm birth. Further prospective large studies are needed to confirm our findings.