Serum hCG Level Measured 5 Days After Vitrified-Warmed Blastocyst Transfer Is Predictive of Outcome Regardless of the Use of Pre-Implantation Genetic Testing

Presented at: ASRM Scientific Congress, 2021

Authors: Bruce Shapiro, Kajal Verma, Ankita Raman, Leah Kaye, Forest Garner, Carrie Bedient

Affiliations: (1) Department of Obstetrics and Gynecology, University of Nevada, Las Vegas, NV, USA; (2) Fertility Center of Las Vegas, Las Vegas, NV


In typical viable natural conceptions, trophoblast invasion is well under way 10-11 days after ovulation, and delayed implantation evidenced by delayed elevation in human chorionic gonadotropin (hCG) levels is a reported predictor of early pregnancy loss. Similarly, serum hCG level on day 5 after thawed blastocyst transfer has been shown to be predictive of outcome. However, it has not previously been shown that this test is predictive of outcome of transfers of genetically screened blastocysts.


The purpose of this study was to evaluate the effect of PGT on the predictive value of peri-implantation hCG levels for early pregnancy outcomes in vitrified-thawed single blastocyst transfers, including clinical pregnancy and ongoing pregnancy.

Materials and Methods:

We performed an IRB-approved retrospective cohort study of all vitrified-warmed single-blastocyst transfers in a 62-month period at a private fertility center. Vitrified-warmed blastocysts were transferred after artificial endometrial preparation on the 6th day of exogenous progesterone exposure. Serum hCG levels were measured 5 and 10 days after transfer to identify pregnancies. Clinical pregnancy was defined by sonographic finding of an intrauterine gestational sac 5-7 weeks after transfer. Ongoing pregnancies were those with fetal cardiac activity at 10 weeks. We evaluated whether serum day 5 hCG ≥5 IU/L was predictive of transfer outcome in PGT and non-PGT cycles. Chi-square tests were used in all comparisons.


There were 901 single-blastocyst transfers in the study period, 646 of which were without PGT while 255 had PGT. Day-5 serum hCG level of  5 IU/L was predictive of early pregnancy outcomes after transfer of PGT and non-PGT blastocysts. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and P-values are shown in Table 1.


Serum hCG level measured in the peri-implantation period is predictive of early pregnancy outcomes in transfer of single PGT and non-PGT blastocysts in artificially prepared cycles.


The serum level of hCG is predictive of outcome as early as 5 days after blastocyst transfer, regardless of the use of PGT.


Table 1.

Sensitivity Specificity PPV NPV Risk Ratio P-value
No PGS testing
Clinical Pregnancy 93.87 85.71 94.08 85.26 6.38 (4.53-8.99) < 0.0001
Ongoing Pregnancy 95.43 63.14 77.85 91.05 8.70 (5.51-13.73) < 0.0001
With PGS testing
Clinical Pregnancy 90.96 79.10 92.43 75.71 3.81 (2.51-5.77) < 0.0001
Ongoing Pregnancy 90.63 57.89 78.38 78.57 3.66 (2.32-5.76) < 0.0001