Dados do Trabalho

Title

The pregnancy outcomes of a good morphology embryos transfer: a comparison between transfer of one euploid embryo versus two morphologically selected embryos

Objective

To compare the transfer of an euploid embryo in relation to two thawed embryos not genetically tested and to correlate with gestational parameters per transfer.

Methods

A retrospective observational study was conducted with 383 patients recruited from a single clinical center. Data were obtained from thawed embryo transfers between January 2020 and December 2021.
Two groups of thawed embryo transfers were analyzed: Biopsy Group – patients who underwent transfer of 1 euploid blastocyst of good morphological quality [≥3BB, Gardner e Schoolcraft (1999)]; Control Group – patients who underwent transfer of 2 blastocysts of good morphological quality without genetic study (≥3BB). Exclusion criteria were: oocyte recipient patients, change in the patient's or partner's karyotype previously detected that predisposes the couple to aneuploidy.
The clinical data of the patients were collected, as well as the follow-up of those who had a confirmed pregnancy and we evaluated gestacional parameters such as: Implantation rate, chemical pregnancy rate (β-hCG > 40mIU/ml); Clinical pregnancy rate (confirmation of gestational sac on ultrasound); live birth rate (≥ 22 weeks); chemical miscarriage rate (β-hCG > 40mIU/ml without visualization of gestational sac); Clinical miscarriage rate (pregnancy loss after visualization of gestational sac); and miscarriage rate per gestational sac.

Results

We identified that the Biopsy group has significantly lower values than the Control Group when comparing the chemical pregnancy rate (59% vs. 70%, p=0,0302) and live birth rate (42% vs. 54%, p = 0,0405). Implantation rate, clinical pregnancy, chemical and clinical miscarriage did not show statistical difference (not shown). Gestational parameters distinguished by patient age are shown in table 1.
When comparing abortions due to gestational sacs in the Biopsy group and the Control group with multiple pregnancies, no differences were found when evaluating all patients. Comparing miscarriages per gestational sacs in the Biopsy group versus the Control group with multiple pregnancies, no differences were found when evaluating all patients (22% vs. 22%, p=1,000), in patients <35 years (9% vs. 21%, p=0,3683) and those aged ≥ 35 years (28% vs. 28%, p=1,0000)(not shown).

Conclusion

We observed that, when the objective is to have a baby at home, the transfer protocol of two good quality embryos still has an advantage in our clinical center in relation to the transfer of a single euploid embryo, resulting in higher rates of chemical pregnancy and live births. Although the transfer of two embryos provides a lower implantation rate in patients aged ≥35 years, this group has lower rates of clinical abortion, providing values of live births equivalent to the Biopsy group. High rates of multiple pregnancies are highlighted, however, the rates related to abortion do not seem to interfere when we transfer 2 embryos.

Keywords

Frozen-thawed embryo transfer, preimplantation genetic testing, embryo morphology, miscarriage.

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