Infertility Due to NonimplantationCompactionNCT05960370
Impact of Endometrial Compaction on Reproductive Outcomes After Cryotransfer of Euploid Embryos in a Natural Cycle
An observational study of Infertility Due to Nonimplantation, run by Instituto Bernabeu at 1 site in Spain.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 50 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Infertility Due to Nonimplantation
- What is being tested?
- Observational non intervention study
- How many people
- 207 participants
- Where
- 1 siteSpain
- Study dates
- 15 Jun 2022to 15 Jul 2025
- How long will I take part?
- 4 Months
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- Women only
- Healthy volunteers accepted
- Adult
Study population: 206 Women between 18-50 years, with primary or secondary infertility, undergoing fertility treatment that includes endometrial preparation in a modified natural cycle for transfer of previously analyzed frozen and euploid embryos.
Who may be able to join
- 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.
Who cannot join
- 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).
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Impact of Endometrial Compaction on Reproductive Outcomes After Cryotransfer of Euploid Embryos in a Natural Cycle: Prospective Cohort Study
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.
Read the detailed description
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.
- Conditions
- Infertility Due to Nonimplantation
- Being tested
- Observational non intervention study
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Observational non intervention studyOther
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.
| Study group | Role | What they receive |
|---|---|---|
| exposed or "compaction" group | 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). Receives: Other: Observational non intervention study | |
| non-exposed "non-compaction" group | 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). Receives: Other: Observational non intervention study |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ongoing pregnancy rate
Presence of an intrauterine pregnancy with positive embryo heartbeat as seen by sonography at 8-10 weeks gestational age.
Measured: 8-10 weeks gestational age.
Secondary outcomes (4)
Biochemical pregnancy loss
Spontaneous pregnancy demise based on decreasing serum b-hCG levels, without an ultrasound evaluation.
Measured: 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.
Measured: 5-6 weeks gestational age.
Ectopic pregnancy
ultrasonic or surgical visualization of a pregnancy outside of the endometrial cavity.
Measured: 5-8 weeks gestational age.
Early pregnancy loss
spontaneous pregnancy demise before 10 weeks of gestational age (before 8th developmental week).
Measured: 5-10 weeks gestational age.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Jul 2023
- Study start15 Jun 2022
- Primary completion15 Jun 2025
- Study completion15 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Infertility Due to NonimplantationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 207 participants (actual)
- Target duration
- 4 Months
Sponsor and investigators
- Lead sponsor
- Instituto Bernabeu
- Sponsor type
- University, hospital or other
- Collaborators
- Universidad Miguel Hernandez de Elche
- Responsible party
- Principal investigator, Dr. Esperanza de la Torre Perez, Instituto Bernabeu
- Investigators
- Juan Carlos J Castillo Farfan, Doctor, Study director, Instituto Bernabeu Alicante
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05960370
- Sponsor's protocol ID
- Compaction Study
- Acronym
- Compaction
- Status last verified
- Mar 2026
- First submitted
- 17 Jul 2023
- Last updated
- 5 Nov 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
De la Torre Perez E, Castillo-Farfan JC, Carratala-Munuera MC, Ortiz JA, Lledo-Bosch B, Olalla Garcia S, Moliner-Renau B, Bernabeu-Garcia A. Endometrial compaction and ongoing pregnancy in modified natural cycle frozen euploid embryo transfer: a prospective multicentre cohort study with standardized transvaginal ultrasound assessment. Hum Reprod. 2026 Oct 25:deag165. doi: 10.1093/humrep/deag165. Online ahead of print.
PubMed 42926142
Study at a glance
From the registry record, last updated by the sponsor on 5 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Endometrial Compaction on Reproductive Outcomes After Cryotransfer of Euploid Embryos in a Natural Cycle: Prospective Cohort Study
- ClinicalTrials.gov ID
- NCT05960370
- Acronym / sponsor ID
- Compaction / Compaction Study
- Conditions
- Infertility Due to Nonimplantation
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 207 participants (actual)
- Lead sponsor
- Instituto BernabeuUniversity, hospital or other
- Collaborators
- Universidad Miguel Hernandez de Elche
- Study start
- 15 Jun 2022 (actual)
- Primary completion
- 15 Jun 2025 (actual)
- Study completion
- 15 Jul 2025 (actual)
- First posted
- 25 Jul 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 4 Months
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| exposed or "compaction" group | – | Other: Observational non intervention study103 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). |
| non-exposed "non-compaction" group | – | Other: Observational non intervention study103 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). |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- 206 Women between 18-50 years, with primary or secondary infertility, undergoing fertility treatment that includes endometrial preparation in a modified natural cycle for transfer of previously analyzed frozen and euploid embryos.
Key inclusion criteria (5 listed)
- 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.
Key exclusion criteria (4 listed)
- 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).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Observational non intervention studyAn additional control scan will be performed vaginally the day of the embryo transfer. Rest of follow up and treatment will be executed as usually. | Other | exposed or "compaction" group, non-exposed "non-compaction" group |
Primary outcome
Ongoing pregnancy rate
Time frame: 8-10 weeks gestational age.
Presence of an intrauterine pregnancy with positive embryo heartbeat as seen by sonography at 8-10 weeks gestational age.
4 secondary outcomes
Biochemical pregnancy loss
Time frame: 9-10 days after the embryo transfer.
Clinical pregnancy
Time frame: 5-6 weeks gestational age.
Ectopic pregnancy
Time frame: 5-8 weeks gestational age.
Early pregnancy loss
Time frame: 5-10 weeks gestational age.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Nov 2026.
- Derived from this study: PubMed 42926142De la Torre Perez E, Castillo-Farfan JC, Carratala-Munuera MC, Ortiz JA, Lledo-Bosch B, Olalla Garcia S, Moliner-Renau B, Bernabeu-Garcia A. Endometrial compaction and ongoing pregnancy in modified natural cycle frozen euploid embryo transfer: a prospective multicentre cohort study with standardized transvaginal ultrasound assessment. Hum Reprod. 2026 Oct 25:deag165. doi: 10.1093/humrep/deag165. Online ahead of print.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Juan Carlos J Castillo Farfan, Doctor study director
Instituto Bernabeu Alicante
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Infertility Due to Nonimplantation, run by Instituto Bernabeu at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ongoing pregnancy rate (time frame: 8-10 weeks gestational age.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05960370, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.