The application of single beta-human chorionic gonadotropin (β-hCG) level measurement in women undergoing single blastocyst transfer

We previously explored the associations between beta-hCG on the 14th day post-embryo transfer (ET) and repro-ductive outcomes and established a series of cutoff values to predict different outcomes. The aim of this study was to explore the parameters associated with beta-hCG levels and establish beta-hCG cutoff values in women un-dergoing single blastocyst transfer. The patients were transferred with either fresh or frozen-thawed blastocysts. Serum beta-hCG levels were compared among different groups. Cutoff values of beta-hCG were established and applied to divide the patients into different groups, among which the beta-hCG groups were compared. Develop day negatively affected beta-HCG levels in those who were pregnant or gave live birth (P < 0.001, 0.008). Inner cell mass significantly affected beta-hCG levels in women who were pregnant or gave live birth (P = 0.013, 0.044). Trophectoderm significantly affected beta-hCG levels in women with most reproductive outcomes, except biochemical pregnancy (BP) (P = 0.184). The cutoff values of beta-hCG for predicting positive outcomes were 194.1, 503.0, 1048.0, and 2590.5 mIU/L. BP rates and adverse pregnancy outcome rates were significantly lower in the higher beta-hCG groups (P < 0.001). Shorter gestational age and lower birth weight and length (P = 0.005, 0.041, 0.003) were observed in the lowest-concentration beta-hCG group. The application of a single beta-hCG measurement was sufficient to predict reproductive outcome in women undergoing blastocyst transfer, under the full consideration of blastocyst parameters. However, the association between beta-hCG and obstetric outcomes remains to be investigated and fully explained.