P-212 βhCG concentration in peripherical maternal blood after single embryo transfer, ongoing pregnancy rates and morphokinetics
Authors: Ojeda Varela M , Aguilar Prieto J , Táboas Lima E , Garrido Puchalt N , Muñoz Muñoz E 
Published: June 2023

Abstract

Study question
Is there a relationship between the concentration of the βhCG hormone in maternal blood, embryo morphokinetics and clinical outcome?

Summary answer
βhCG concentration is related to trophoectoderm quality, abortion rate and live birth rate, but not to embryo morphokinetics

What is known already
Measurement of βhCG has been widely used for early pregnancy detection after assisted reproduction treatments.
Shortly after embryo implantation, trophoblastic βhCG is detectable in maternal blood, However, βhCG concentration in several women showed high variability, and embryo implantation also depends on endometrial receptivity, what means that in early stages, everything affecting endometrial receptivity, may affect βhCG concentration.
Early high βhCG concentration has been related with higher pregnancy rate, but there are scarce information concerning relationship between βhCG early value and ongoing pregnancy rates

Study design, size, duration
Retrospective biomedical research of 508 patients having single embryo transfer of fresh embryos at IVIRMA VIGO clinic between 2017 and 2021 to analyse the relation between βhCG concentration, and embryo quality, embryo morphokinetics and ongoing pregnancy rate.
Patients with recurrent miscarriage, advanced maternal age, uterine pathologies and severe male factor were excluded of the study.
βhCG was measured in the peripherical maternal blood 13 days after embryo transfer

Participants/materials, setting, methods
All the embryos were generated by ICSI and were cultured in a time-lapse incubator under a 37ºC, 6% CO2 and 5% O2 atmosphere.
T-Student and Youden test between embryo kinetics and βhCG values, Pearson correlation test to compare gestational successes with kinetic embryo data, and a linear regression model with βhCG like response variable and morphokinetic data like explanation variables were employed

Main results and the role of chance
βhCG concentration was greater in trophoectoderm A embryos compared to B and C (ASEBIR classification), 619.53 UI/ml, IC95% (483.16-755.90), 442.24 UI/ml, IC95% (350.18-534.31), 269.95 UI/ml, IC95%(88.88-451.01) (p = 0.038) respectively and there was a trend with Inner cell mass quality, being greater also in quality A vs B and C (p = 0.053)
Patients who had a clinic abortion showed lower βhCG concentration compared to those with ongoing pregnancy and live birth, 385.37 UI/ml, IC95% (268.45-502.28) vs 987.53 IU/ml, IC95% (845.03-1130.03).
T-student test linear regression analysis and Youden index, with βhCG cut-off points of 10 IU/ml and 100 IU/ml were employed, to analyze relationship between βhCG concentration and embryo morphokinetics, but it was not significant in any of the parameters analyzed

Limitations, reasons for caution
There is a limited sample size and data were obtained from a retrospective study. Patients and donor oocytes were analyzed in this study, although no differences were found when they compared

Wider implications of the findings
This study shows that a top quality trophoectoderm produces more βhCG, and that could be a predictive value for ongoing pregnancy

Trial registration number
1712-VGO-122-EM