RELATIONSHIP BETWEEN SERUM PROGESTERONE CONCENTRATION AND PREGNANCY RATE IN CLEAVAGE-STAGE FROZEN-THAWED EMBRYO TRANSFER AFTER ARTIFICIAL ENDOMETRIAL PREPARATION

Problem Statements

The embryo cryopreservation technique is an increasingly used therapeutic option in Artificial Reproductive Tecnhique (ART). There is general consensus on the advantage to transfer a cryopreserved blastocyst rather than a cleavage-stage embryo. Nevertheless, in low-prognosis patients, a prolongation of culture until day 5 or 6 could not represent the best option. In such cases, it might be useful to freeze embryos on day 2 or 3.
A correlation between the serum progesterone value, on or before the day of blastocyst transfer in Frozen Embryo Transfer (FET) after artificial endometrial preparation, and the success of the procedure has been shown. Different cut-off have been proposed for customizing luteal support.
No data is currently available on serum progesterone value as a predictor of FET outcome in cleavage-stage. The search of such cut-off represented our primary endpoint.

Methods

We performed a prospective observational cohort study. 42 low-prognosis patients aged 28-39 years candidated for an in vitro fertilization cycle were enrolled between October 2022 and July 2023.
All patients underwent FET after an endometrial preparation protocol with hormone replacement therapy (HRT). Double blood sampling was performed, the day before (T-1) and the day of the procedure (T0), in order to assess the serum progesterone value and after 14 days to assess human chorionic gonadotropine.

Results

The average serum progesterone value was 9.06 ng/mL at time T-1 and 12.93 ng/mL at time T0, with a wide range of distribution. No significant cut-off was found correlating with gravid outcome. Focusing on the difference between progesterone values measured at time T-1 and at time T0, the growth trend appeared to be higher in women with gravid success (P value 0.07).

Conclusions

No specific cut-off of serum progesterone levels, measured at T-1 and at T0, was found correlated with biochemical pregnancy rate in our study.
In pregnant patients a significantly higher delta PT0-PT-1, close to statistical significance, was shown compared with nonpregnant patients. The current study suggests the possibility to consider the progesterone delta value T0-T-1 as a useful parameter for customizing luteal support and increase pregnancy rate in FET after HRT.