Association between early βhCG kinetics, blastocyst morphology and pregnancy outcome in a single-blastocyst transfer program

Impact of trophectoderm biopsy on serum β-hCG dynamics: PGT cycles vs. non-PGT cycles

PURPOSE

Pre-implantation genetic testing (PGT), which involves trophectoderm (TE) biopsy, is commonly used to detect genetic abnormalities in embryos. However, its impact on serum β-human chorionic gonadotropin (β-hCG) levels in early pregnancy remains a topic of debate. This study evaluated the effects of TE biopsy on β-hCG dynamics. Serum β-hCG levels on days 9 and 11 post-blastocyst transfer were compared between PGT and non-PGT cycles. Additionally, β-hCG thresholds were explored as potential prognostic markers for success in assisted reproductive technology (ART).

METHODS

This retrospective cohort study was conducted at the Memorial Şişli Hospital, İstanbul, Türkiye, between January 2012 and January 2021. The patients undergoing frozen-thawed single blastocyst transfer were divided into PGT (1698 cycles) and non-PGT (1830 cycles) groups. The serum β-hCG levels on days 9 and 11 after embryo transfer (ET) and the rate of β-hCG increase were compared.

RESULTS

In both groups, higher baseline β-hCG levels and rates of increase were correlated with live birth outcomes than with clinical or biochemical pregnancy loss (p < 0.001). PGT cycles showed lower baseline β-hCG levels across all pregnancy outcomes, but no significant difference in β-hCG increase rates (p > 0.05). After adjusting for confounding factors, PGT cycles were not found to be significantly associated with β-hCG levels.

CONCLUSION

Serum β-hCG dynamics strongly predict live birth and clinical pregnancy. PGT did not significantly affect β-hCG levels after adjustment for confounders.

Relationship between fresh single embryo morphology scores and serum HCG values at 14 days and 14-18-day doubling values

RESEARCH QUESTION

What is the effect of embryo morphology score on 14-day β-HCG levels and 14-18-day β-HCG doubling values, and do they have differences in day-3 embryo or day-5 blastocyst transfers?

DESIGN

Retrospective analysis of 4434 fresh cycles of single embryo transfers (SET) with β-HCG ≥15 mIU/ml on day 14 after transfer via IVF and ICSI. The correlation between embryo morphology score and 14-day β-HCG was examined. Doubling of 14-18 day β-HCG was analysed in 2628 cycles to determine correlations with embryo morphology score.

RESULTS

In day-3 SET, number of embryonic cells was positively correlated with 14-day post-transfer β-HCG values (R = 0.076; P = 0.013). No significant correlation was observed between the grade of the transferred embryos and the 14-18-day serum β-HCG doubling values. In day-5 single blastocyst transfers, the degree of blastocyst expansion, trophoblast cell and inner cell mass (ICM) grades demonstrated a significant positive correlation with 14-day post-transfer β-HCG (P < 0.001, P = 0.014, P = 0.003). Degree of blastocyst expansion was significantly correlated with 14-18-day β-HCG doubling values (R = -0.051, P = 0.027). Grades of the ICM and trophoblast cells showed no significant correlation with 14-18-day β-HCG doubling values.

CONCLUSION

In fresh SET, embryo morphology score influences 14-day β-HCG values in day-3 embryos and day-5 blastocyst transfers. Embryo morphology score in day-3 SET does not affect 14-18-day β-HCG doubling values. Degree of blastocyst expansion significantly affects 14-18-day β-HCG doubling values in day-5 blastocyst transfers.

Recryopreservation impairs blastocyst implantation potential via activated endoplasmic reticulum stress pathway and induced apoptosis

Recryopreservation (recryo) is occasionally applied in clinical, while the underlying mechanism of impaired clinical outcomes after recryo remains unclear. In this study, frozen embryo transfer (FET) cycles of single blastocyst transfer in an academic reproductive medicine center were enrolled. According to the number of times blastocysts experienced cryopreservation, they were divided into the cryopreservation (Cryo) group and the Recryo group. Donated human blastocysts were collected and detected for mechanism exploration. It was found that recryo procedure resulted in impaired blastocyst developmental potential, including decreased implantation rate, reduced biochemical pregnancy rate, declined clinical pregnancy rate, higher early miscarriage rate, and lower live birth rate. Moreover, recryo led to impaired trophectoderm (TE) function, exhibiting lower human chorionic gonadotropin levels 12 days after FET. In addition, single-cell RNA sequencing showed that the expression of genes involved in cell adhesion and embryo development were altered. More specifically, activated endoplasmic reticulum (ER) pathway and induced apoptosis were further verified by immunofluorescence and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay involving in the recryo procedure. In conclusion, recryo could interfere with the process of blastocyst implantation by impairing TE function, affecting blastocyst adhesion, activating ER stress pathway and inducing apoptosis. It provides caution to embryologists about the potential risk of recryopreservation.

Prediction of live birth in vitrified-warmed 1PN-derived blastocyst transfer: Overall quality grade, ICM, TE, and expansion degree

Background: Numerous studies have reported that transfer of blastocysts derived from monopronuclear (1PN) zygotes achieved live births. However, the potential value of morphology grading for the prediction of 1PN blastocyst viability is unclear, and the blastocyst selection criterion for successful pregnancy has not been set up yet. The aim of this study is to assess the ability of the blastocyst morphology grading system based on three parameters, namely, inner cell mass (ICM), trophectoderm (TE), and expansion degree and to predict outcomes of a cycle with single 1PN blastocyst transfer.

Methods: A total of 266 vitrified-warmed 1PN-derived blastocyst transfer cycles for IVF treatment at Shanghai Ninth People’s Hospital between 2007 and 2020 were included. The study was performed on single blastocyst transfers. Electronic records of patients were retrospectively analyzed. In the current study, the blastocysts were classified into three groups: “good,” 3-6AA, 3-6AB, 3-6BA; “medium,” 3-6BB, 3-6AC, 3-6CA; and “poor,” 3-6BC, 3-6CB, 3-6CC. The basal characteristics, embryo grading, and clinical outcomes were compared between the three groups. The association of morphology parameters with pregnancies and live births was analyzed. Logistic regression was adopted to set up a prediction model of live births.

Results: Transfer of the good-quality blastocysts achieved significant higher pregnancies (biochemical pregnancy: 59%; clinical pregnancy: 56.4%, and live birth 48.7%) than those in the group of the medium (biochemical pregnancy: 59%; clinical pregnancy: 49.6%; live birth: 40.4%) or poor-quality (biochemical pregnancy: 38.4%; clinical pregnancy: 34.9%; live birth: 26.7%) blastocysts (p &lt; 0.05). There was a significant association between ICM and live birth. A prediction model of live births involving ICM, TE, and expansion degree was set up.

Conclusion: In 1PN transfer cycles, a higher overall blastocyst quality is shown to correlate most strongly with optimal pregnancy and live birth outcomes. The selection of high-quality blastocysts for transfer should consider the ICM score first. The prediction model of live births based on ICM, TE, and expansion degree may help predict successful pregnancy in 1PN single-blastocyst transfer cycles.

Biological relevance of trophectoderm morphology: initial β-hCG measurements correlate with trophectoderm grading on euploid frozen embryo transfers

OBJECTIVE

To analyze the correlation between TE grading and initial β-hCG serum level after single euploid embryo transfer. Secondarily, to explore the association between TE grading with subsequent IVF outcomes.

DESIGN

Retrospective cohort analysis.

SETTING

Single, academic, private infertility and assisted reproductive care institute.

PATIENTS OR OTHER PARTICIPANTS

Infertility patients who underwent a single euploid embryo transfer that resulted in a positive pregnancy test.

INTERVENTION(S)

β-hCG measurements.

MAIN OUTCOME MEASURE(S)

Correlation between TE grade with first β-hCG measurement. Second outcome measurements included ongoing pregnancy, biochemical pregnancy loss, and clinical pregnancy loss rates.

RESULTS

2,798 cases were analyzed. A significant difference in initial β-hCG measurement among groups (TE A: median 143.4 mIU/mL IQR 79.2-211.2; TE B: 119 mIU/mL IQR 57.1-177.8; TE C: 82.4 mIU/mL IQR 36.3-136.4, p ≤ 0.0001) was observed. There was a significant correlation found between the TE grade and β-hCG measurements (p ≤ 0.0001, r2 = 0.10). TE grade was not associated with higher odds of biochemical pregnancy loss (TE A vs. TE B: aOR 1.01 CI95% 0.97-1.05; TE A vs. TE C: aOR 1.03 CI95% 0.98-1.08), or higher odds of clinical pregnancy loss (TE A vs. TE B: aOR 1.02 CI95% 0.98-1.05; TE A vs. TE C: aOR 1.03 CI95% 0.98-1.07).

CONCLUSIONS

In patients with euploid embryos, TE grade correlates with the first pregnancy test measurement of β-hCG. We propose this finding helps to appoint a relevant link between morphology assessment and early embryo development in vivo.

Combined analysis of human chorionic gonadotrophin concentrations at different time points after frozen-thawed blastocyst transfer can improve our ability to predict the pregnancy outcomes of single gestations

In this study, we conducted a retrospective single-centre study of 1664 singleton pregnancies derived from frozen-thawed blastocyst transfer between January 2017 and December 2018. Analysis showed that there were 596 early pregnancy losses and 1068 ongoing pregnancies. We compared serum HCG (human chorionic gonadotophin) concentrations on days 12, 14, 19, and 21, between the pregnancy loss group and the ongoing pregnancy group. The cut-off level of HCG at each time point was calculated to predict pregnancy outcome. Joint analysis of two single HCG levels taken one week apart was carried out to improve predictive accuracy. The levels of HCG at four time points were significantly lower in the early pregnancy loss group than in the ongoing pregnancy group. According to the area under ROC (receiver operating characteristic curve) curves, all levels of HCG taken at four time points showed good ability to predict the outcome of pregnancy. The joint analysis of two single HCG levels taken one week apart further improved the accuracy of prediction.Impact statementWhat is already known on this subject? Multiple studies have shown that the maternal level of serum HCG is the best parameter for predicting the course of pregnancy.What do the results of this study add? The levels of HCG on days 12, 14, 19 and 21 were significantly lower in the early pregnancy loss group than in the group of ongoing pregnancies. According to the area under ROC curves, all levels of HCG taken at four time points showed a good ability to predict the outcome of pregnancy.What are the implications of these findings for clinical practice and/or further research? The joint analysis of two single HCG levels, taken one week apart, further improved the accuracy of prediction.

Blastocyst morphology has no relationship with serum β-hCG levels and live birth rates once pregnant

OBJECTIVE

What is the role of blastocyst morphology on day16 β-hCG serum levels and pregnancy outcomes among patients who conceived through IVF cycles with single fresh Gardner's scored blastocyst transfers.

STUDY DESIGN

A retrospective cohort study conducted at a single academic fertility center between January 2013 and December 2017. A total of 643 pregnancies were included in the study.

RESULTS

The patients were divided into 5 groups according to Gardner's blastocysts grade of the ICM and the TE (grade), and into 4 groups according to blastocyst Gardner's degree of blastocoel expansion (stage). No significant differences were found between the different morphologic groups and day16 β-hCG serum levels, clinical pregnancy rates and live births. A weak significant correlation was observed between Gardner's blastocysts grade and day 16 β-hCG (Correlation Coefficient r= -0.098, p = .014) this correlation remained significant after controlling for confounders. (r= -0.099 p = . 013). A weak significant correlation was observed between Gardner's stage and day 16 β-hCG (Correlation Coefficient r = 0.086, p = 0.029) this correlation lost significance after controlling for confounders. (r = 0.055, p = 0.340). When evaluating predictors of live birth using multivariate logistic regression, blastocyst grade (p = 0.33) and stage (p = 0.65), at transfer, were not associated with live births, when controlling for confounding effects.

CONCLUSION

Once the patient conceives after IVF with single blastocyst, none of the morphological parameters have a strong impact on the day16 serum level of β-hCG. Among women who conceived, blastocyst grade and stage were not associated with live births.

Early Serum hCG in IVF: Are We Trending in the Right Direction?

Human chorionic gonadotropin (hCG) measurements may be the earliest indicator of fertility cycle success, available several weeks before an ultrasound would be diagnostic for pregnancy. Outcomes of these cycles are high stakes for a couple, and the earliest reassurance of a normal pregnancy would be beneficial for their well-being. Additionally, earlier diagnosis can allow for more rapid management by providers in the case of abnormal pregnancies. Therefore, establishing normal values for initial hCG level and early hCG kinetics is of great interest. There are many factors involved in assisted reproductive techniques that may lead to alterations in hCG kinetics when compared with spontaneous pregnancies. We aim to characterize normal hCG values for in vitro fertilization (IVF) pregnancies and review how different aspects of the IVF process may alter these trends in order to establish how best to counsel patients during the waiting period.