Predicting in vitro fertilization success: establishing human chorionic gonadotropin cutoffs after frozen embryo transfers for untested and preimplantation genetic tested embryos
摘要
The early post-embryo transfer period lacks well-defined beta-human chorionic gonadotropin (hCG) thresholds to distinguish viable from non-viable pregnancies after frozen embryo transfer (FET). This study aimed to identify a day-14 post-FET hCG cutoff that predicts fetal heart tones (FHT) and live birth (LB), and to assess its utility in guiding decisions regarding continuation of progesterone support.
MethodsA retrospective cohort study was conducted at a single academic center including 1681 single-embryo FETs from 2021 to 2023. Demographic, cycle, and embryologic variables were extracted from medical records. Serum hCG levels were measured 14 days post-FET. Receiver operating characteristic analyses identified optimal hCG thresholds for predicting FHT and LB. Outcomes were compared using appropriate parametric and nonparametric statistical tests.
ResultsOverall, 59.0% of transfers resulted in FHT and 56.0% in LB. A hCG cutoff of 391.7 mIU/mL predicted LB with 96.3% sensitivity and 82.7% specificity (AUC = 0.936). Patients with hCG ≥ 391.7 mIU/mL had markedly higher FHT (92.1%) and LB (87.6%) rates than those below this threshold (6.0% and 5.4%, respectively). The lowest hCG associated with LB was 119.9 mIU/mL. Findings were consistent in the PGT-A subgroup.
ConclusionA day-14 hCG value of ≥ 391.7 mIU/mL strongly predicts FHT and LB after FET and may serve as a clinically meaningful threshold for early counseling and decisions regarding progesterone continuation. However, rare live births occur at lower levels, underscoring the need for individualized interpretation and clinical context.