Abstract
Abstract
Aim
To evaluate the predictive value of serum beta-human chorionic gonadotropin (β-hCG) measured at 11–14 days after frozen-thawed embryo transfer (FET) for clinical pregnancy, and to explore the potential associations of blastocyst transfer and other serum markers (total protein, albumin, red blood cell distribution width) with pregnancy outcomes.
Methods
A retrospective cohort study was performed on 268 infertile patients who underwent FET at our hospital from January 2025 to December 2025. Patients were divided into clinical pregnancy (
n
= 132) and non-pregnancy (
n
= 136) groups. Baseline characteristics and serum markers (TP, Alb, RDW) measured on day 7 post-transfer were compared between groups. The predictive performance of β-hCG was evaluated using receiver operating characteristic (ROC) curve analysis. Univariate and multivariable logistic regression analyses were performed to identify factors independently associated with clinical pregnancy.
Results
Serum β-hCG levels were significantly higher in the clinical pregnancy group (
P
P
P
= 0.10) but was not statistically significant in multivariable analysis (OR = 1.39, 95% CI: 0.30–6.32,
P
= 0.67). TP showed a trend towards an association in univariate analysis (OR = 0.95, 95% CI: 0.89–1.01,
P
= 0.10) but was not statistically significant, and was not an independent factor for clinical pregnancy (OR = 0.84, 95% CI: 0.68–1.03,
P
= 0.10). Alb and RDW showed no significant differences between groups.
Conclusion
In this retrospective cohort study, serum β-hCG measured 11–14 days after FET demonstrated excellent predictive performance for clinical pregnancy (AUC 0.994). While both blastocyst transfer and total protein showed trends toward association in univariate analysis, neither remained an independent predictor in multivariable analysis. Other serum markers (Alb, RDW) provided no incremental predictive value beyond β-hCG. These findings support the clinical utility of early post-FET β-hCG measurement; however, the potential roles of blastocyst transfer and total protein require further investigation in larger, prospective cohorts.