Impact of Endometrial Compaction on Reproductive Outcomes After Cryotransfer of Euploid Embryos in a Natural Cycle

Study Overview
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Brief Summary
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Multicenter prospective observational cohort study, comparing ongoing pregnancy rates in natural cycles for euploid embryo transfer in patients who present endometrial compaction at the time of the transfer versus those who have a stable or greater endometrial thickness with respect to the estrogenic phase.

Detailed Description
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Multicenter prospective observational cohort study. Based on our sample size calculation, the study group will consist of 206 women (exposed or compaction group: 103 women with a decrease of ≥ 5% in endometrial thickness between the estrogenic phase and the day of embryo transfer; non-exposed non-compaction group: 103 women with similar or greater endometrial thickness between these time points). The main objective of this study is to compare the ongoing pregnancy rates in natural cycles for euploid embryo transfer in patients who present endometrial compaction at the time of transfer versus those who with a stable or greater endometrial thickness with respect to the estrogenic phase. The estimated duration of the study is 24-30 months. Inclusion criteria are: 18 to 50 years of age, with primary or secondary infertility, subjected to endometrial preparation in a modified natural cycle for transfer of a genetically euploid blastocyst, from their own oocyte or oocyte donation, with a normal uterine cavity. Exclusion criteria are: uterine or endometrial disease (e.g., multiple myomatosis, severe adenomyosis, Asherman syndrome, refractory endometrium), conditions that prevent correct ultrasound assessment (tilted uterus), or a history of recurrent implantation failure or repeated miscarriages.

Official Title
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Impact of Endometrial Compaction on Reproductive Outcomes After Cryotransfer of Euploid Embryos in a Natural Cycle: Prospective Cohort Study

Conditions
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Infertility Due to Nonimplantation

Intervention / Treatment
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* Other: Observational non intervention study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 18 to 50 years Primary or secondary infertility Normal uterine cavity Endometrial preparation in a modified natural cycle for single embryo transfer Embryo in blastocyst state from own oocyte or oocyte donation cycles, who had normal results on preimplantation genetic testing for aneuploidy (PGT-A) via trophectoderm biopsy. Exclusion Criteria: Uterine or endometrial disease (multiple myomatosis [>3 fibroids of > 3 cm], adenomyosis, Asherman syndrome) Difficulties in correctly measuring endometrial thickness due to a retroverted or tilted uterus History of recurrent implantation failure (3 or more transferred blastocysts of good quality, from their own oocyte [<35 years] or oocyte donation); recurrent early Pregnancy Loss (the loss of two or more pregnancies before 10 weeks of gestational age. Suboptimal endometrial response (endometrium < 6 mm on the day of ovulation triggering).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| exposed or compaction group<br>103 women with a decrease of ≥ 5% in endometrial thickness between the estrogenic phase (ovulation induction day) and the day of embryo transfer (7 days after ovulation induction). | Other: Observational non intervention study<br>* An additional control scan will be performed vaginally the day of the embryo transfer. Rest of follow up and treatment will be executed as usually.<br>|
| non-exposed non-compaction group<br>103 women with similar or greater endometrial thickness between the estrogenic phase (ovulation induction day) and the day of embryo transfer (7 days after ovulation induction). | Other: Observational non intervention study<br>* An additional control scan will be performed vaginally the day of the embryo transfer. Rest of follow up and treatment will be executed as usually.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ongoing pregnancy rate | Presence of an intrauterine pregnancy with positive embryo heartbeat as seen by sonography at 8-10 weeks gestational age. | 8-10 weeks gestational age. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Biochemical pregnancy loss | Spontaneous pregnancy demise based on decreasing serum b-hCG levels, without an ultrasound evaluation. | 9-10 days after the embryo transfer. | 
| Clinical pregnancy | A pregnancy diagnosed by ultrasonographic visualization of one or more gestational sacs or definitive clinical signs of pregnancy. | 5-6 weeks gestational age. | 
| Ectopic pregnancy | ultrasonic or surgical visualization of a pregnancy outside of the endometrial cavity. | 5-8 weeks gestational age. | 
| Early pregnancy loss | spontaneous pregnancy demise before 10 weeks of gestational age (before 8th developmental week). | 5-10 weeks gestational age. |