Fertility PreservationNCT07877025
Follicular Flushing Versus Direct Aspiration in Transabdominal Oocyte Retrieval
An observational study of Fertility Preservation, run by Centrum Clinic IVF Center at 2 sites in Turkey (Türkiye).
Trial summary
The goal of this observational study is to learn whether rinsing the egg sacs (follicles) during egg collection helps doctors collect more eggs in women with low egg reserve. Participants are unmarried women aged 18 to 42 who are freezing their eggs and who chose to have eggs collected through the abdomen instead of… Read more about this study
- Who is it for?
- Ages 18 to 42 years, women only
- Conditions the study is for
- Fertility Preservation
- How many people
- 180 participants
- Where
- 2 sitesTurkey (Türkiye)
- Study dates
- 20 Aug 2026to 30 Dec 2026
- How long will I take part?
- 6 Months
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 42 years
- Women only
- No healthy volunteers
- Adult
Study population: Consecutive women aged 18-42 years with diminished ovarian reserve (serum AMH ≤1.0 ng/mL) who are undergoing oocyte cryopreservation for fertility preservation at two IVF centres in Turkey (Ankara and İstanbul). All of them decline transvaginal access for cultural or personal reasons and undergo transabdominal ultrasound-guided oocyte retrieval. Women who receive direct aspiration at one centre are compared with women who receive follicular flushing at the other, as each centre's routine retrieval technique.
Who may be able to join
- Women aged 18-42 years
- Serum anti-Müllerian hormone (AMH) ≤1.0 ng/mL
- Planned oocyte cryopreservation for fertility preservation
- Decline of transvaginal oocyte retrieval for cultural or personal reasons, with transabdominal retrieval chosen as the preferred route
- Eligible for oocyte cryopreservation under Turkish regulations
- At least one follicle ≥17 mm on the day of ovulation trigger
- Written informed consent
Who cannot join
- Conditions that prevent safe transabdominal access, such as extensive pelvic adhesions or unfavourable ovarian position
- Previous major abdominal or pelvic surgery likely to interfere with the procedure
- Active pelvic infection
- Suspected ovarian malignancy
- Contraindications to sedation or oocyte retrieval
- Retrieval performed outside local regulatory requirements
- Incomplete clinical or laboratory data
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)2 sites, 2 recruiting
- Recruiting
Centrum Clinic IVF Center
Ankara, Ankara, 06800
Emre G Pabuccu, Prof., 05324147844, emregpabuccu@gmail.com
emregpabuccu@gmail.com
- Recruiting
Brussels IVF Center
Istanbul, Istanbul, 06700
Cem Çelik, Prof., 0090 532 420 5365, cemcel@yahoo.com
About this study
The goal of this observational study is to learn whether rinsing the egg sacs (follicles) during egg collection helps doctors collect more eggs in women with low egg reserve. Participants are unmarried women aged 18 to 42 who are freezing their eggs and who chose to have eggs collected through the abdomen instead of the vagina. Low egg reserve means a blood level of anti-Müllerian hormone (AMH) of 1 ng/mL or lower.
The main questions it aims to answer are:
Read more
Does rinsing the follicles raise the total number of eggs collected? Does rinsing the follicles raise the number of mature eggs that can be frozen?
Researchers will compare two egg collection methods, each used routinely at one of two IVF centres in Turkey:
Direct aspiration: each follicle is emptied once with a single-channel needle, with no rinsing.
Follicular flushing: a double-channel needle is used. If no egg is found after the first try, the follicle is rinsed with warm fluid and emptied again, up to six times.
Participants will:
Take fertility hormone injections for about 8 to 12 days so that several follicles grow Have their eggs collected through the abdomen under sedation, guided by ultrasound Have their mature eggs frozen for future use
Read the detailed description
Background and rationale. Transabdominal ultrasound-guided oocyte retrieval (OPU) is used for oocyte cryopreservation in women who decline the transvaginal route for cultural or personal reasons. The transabdominal route tends to give a less favourable needle trajectory, longer needle travel through tissue and less stable follicle access. Each of these can raise the chance that the cumulus-oocyte complex (COC) stays in the follicle after the first aspiration. Follicular flushing is meant to recover these retained COCs. Randomised trials and meta-analyses in conventional transvaginal IVF have shown no consistent benefit from flushing. Some data suggest it may help in poor responders, where each lost oocyte matters more. No study has looked at flushing during transabdominal OPU in women with diminished ovarian reserve (DOR).
Design. This is a two-centre comparative cohort study. Each centre used one retrieval technique as its routine practice, so the technique was assigned by centre and not by randomisation. Centre A (Brussels IVF Centre, İstanbul) used direct aspiration only. Centre B (Centrum Clinic IVF Centre, Ankara) used systematic follicular flushing. At each centre, one experienced operator performed all procedures.
Ovarian stimulation. Patients were stimulated on either a GnRH antagonist protocol or a progestin-primed ovarian stimulation (PPOS) protocol. Recombinant FSH was started at 225-300 IU/day, and hMG was added when clinically indicated. Final oocyte maturation was triggered with a single dose of recombinant hCG, and OPU was performed 36 hours later.
Retrieval technique. Both centres used 17-gauge Wallace® needles (CooperSurgical, Trumbull, CT, USA) under transabdominal ultrasound guidance, with a constant aspiration pressure of 140 mmHg.
Direct aspiration: each follicle was aspirated once with a single-lumen needle and was not flushed.
Follicular flushing: a double-lumen needle was used. If a follicle yielded no COC on the first aspiration, it was flushed with 3 mL of pre-warmed (37 °C) culture medium and aspirated again. This was repeated until a COC was found or six flushes had been done.
Laboratory handling. Embryologists assessed the COCs immediately after retrieval. After denudation, oocytes were classified by nuclear maturity as metaphase II (MII), metaphase I (MI), germinal vesicle (GV) or degenerated. MII oocytes were vitrified following each laboratory's validated standard operating procedures.
Patient preference documentation. Before retrieval, every patient filled in a standard intake form stating her preferred retrieval route (transabdominal or transvaginal). These forms were collected as part of routine care.
Statistical analysis. Normality was tested with the Shapiro-Wilk test. Continuous variables were compared with Welch's t-test or the Mann-Whitney U test, as appropriate. Categorical variables were compared with the chi-square test or Fisher's exact test. Two-sided P < 0.05 was taken as significant. Analyses were run in Python 3.11 (SciPy 1.11, pandas 2.0).
Potential sources of bias. Technique was confounded with centre and operator. The groups also differed in stimulation protocol mix (PPOS was used more at Centre B), so differences in stimulation duration and progesterone levels are expected. Embryology laboratories were not standardised between centres.
- Conditions
- Fertility Preservation
- Keywords
- cryopreservation, oocyte aspiration, follicular flushing, transabdominal aspiration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Direct Aspiration | Women with diminished ovarian reserve (AMH ≤1.0 ng/mL) undergoing transabdominal ultrasound-guided oocyte retrieval for oocyte cryopreservation at Centre A (İstanbul). One operator performs every retrieval with a 17-gauge single-lumen needle at a constant aspiration pressure of 140 mmHg. Each follicle is aspirated once and is not flushed. Direct aspiration is the centre's routine retrieval technique. | |
| Follicular Flushing | Women with diminished ovarian reserve (AMH ≤1.0 ng/mL) undergoing transabdominal ultrasound-guided oocyte retrieval for oocyte cryopreservation at Centre B (Ankara). One operator performs every retrieval with a 17-gauge double-lumen needle at a constant aspiration pressure of 140 mmHg. When the first aspiration of a follicle yields no cumulus-oocyte complex, the follicle is flushed with 3 mL of pre-warmed (37 °C) culture medium and aspirated again. This is repeated until a complex is recovered, up to six flushes. Follicular flushing is the centre's routine retrieval technique. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Metaphase II (MII) Oocytes Retrieved per Participant
The number of mature oocytes per participant. After denudation, embryologists classify each retrieved oocyte by nuclear maturity, and those with a visible first polar body are counted as MII.
Measured: Day of oocyte retrieval (assessed within 2 hours after retrieval)
Secondary outcomes (2)
Follicle-to-Oocyte Index (FOI)
The number of oocytes retrieved divided by the antral follicle count (AFC) at the start of ovarian stimulation, multiplied by 100 and expressed as a percentage.
Measured: From start of ovarian stimulation to day of oocyte retrieval (approximately 2 weeks)
Oocyte Maturation Rate
The number of metaphase II (MII) oocytes divided by the total number of oocytes retrieved, multiplied by 100 and expressed as a percentage per participant.
Measured: Day of oocyte retrieval
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Oct 2026
- Study start20 Aug 2026
- Primary completion20 Dec 2026 (estimated)
- Study completion30 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fertility PreservationStudies 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
- 180 participants (estimated)
- Target duration
- 6 Months
Sponsor and investigators
- Lead sponsor
- Centrum Clinic IVF Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Emre Göksan Pabuçcu, Centrum Clinic IVF Center
- Investigators
- Emre G pabuçcu, Prof., Study director, Ufuk University School of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07877025
- Sponsor's protocol ID
- 2026-1
- Status last verified
- Oct 2026
- First submitted
- 9 Oct 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be made publicly available. The study population is small and culturally sensitive (unmarried women undergoing transabdominal oocyte retrieval for fertility preservation), and participants were not asked to consent to public data sharing. Releasing individual-level data could therefore risk re-identification. Under Turkish personal data protection law (KVKK, Law No. 6698), health data are a special category of personal data with restricted transfer. De-identified aggregate data underlying the published results may be made available by the corresponding author on reasonable request, subject to approval by the institutional ethics committees and a data-sharing agreement.
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Follicular Flushing Versus Direct Aspiration in Transabdominal Oocyte Retrieval
- ClinicalTrials.gov ID
- NCT07877025
- Acronym / sponsor ID
- 2026-1
- Conditions
- Fertility Preservation
- Keywords
- cryopreservation, oocyte aspiration, follicular flushing, transabdominal aspiration
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 180 participants (estimated)
- Lead sponsor
- Centrum Clinic IVF CenterUniversity, hospital or other
- Study start
- 20 Aug 2026 (actual)
- Primary completion
- 20 Dec 2026 (estimated)
- Study completion
- 30 Dec 2026 (estimated)
- First posted
- 15 Oct 2026 (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.
The goal of this observational study is to learn whether rinsing the egg sacs (follicles) during egg collection helps doctors collect more eggs in women with low egg reserve. Participants are unmarried women aged 18 to 42 who are freezing their eggs and who chose to have eggs collected through the abdomen instead of the vagina. Low egg reserve means a blood level of anti-Müllerian hormone (AMH) of 1 ng/mL or lower.
The main questions it aims to answer are:
Does rinsing the follicles raise the total number of eggs collected? Does rinsing the follicles raise the number of mature eggs that can be frozen?
Researchers will compare two egg collection methods, each used routinely at one of two IVF centres in Turkey:
Direct aspiration: each follicle is emptied once with a single-channel needle, with no rinsing.
Follicular flushing: a double-channel needle is used. If no egg is found after the first try, the follicle is rinsed with warm fluid and emptied again, up to six times.
Participants will:
Take fertility hormone injections for about 8 to 12 days so that several follicles grow Have their eggs collected through the abdomen under sedation, guided by ultrasound Have their mature eggs frozen for future use
Detailed description
Background and rationale. Transabdominal ultrasound-guided oocyte retrieval (OPU) is used for oocyte cryopreservation in women who decline the transvaginal route for cultural or personal reasons. The transabdominal route tends to give a less favourable needle trajectory, longer needle travel through tissue and less stable follicle access. Each of these can raise the chance that the cumulus-oocyte complex (COC) stays in the follicle after the first aspiration. Follicular flushing is meant to recover these retained COCs. Randomised trials and meta-analyses in conventional transvaginal IVF have shown no consistent benefit from flushing. Some data suggest it may help in poor responders, where each lost oocyte matters more. No study has looked at flushing during transabdominal OPU in women with diminished ovarian reserve (DOR).
Design. This is a two-centre comparative cohort study. Each centre used one retrieval technique as its routine practice, so the technique was assigned by centre and not by randomisation. Centre A (Brussels IVF Centre, İstanbul) used direct aspiration only. Centre B (Centrum Clinic IVF Centre, Ankara) used systematic follicular flushing. At each centre, one experienced operator performed all procedures.
Ovarian stimulation. Patients were stimulated on either a GnRH antagonist protocol or a progestin-primed ovarian stimulation (PPOS) protocol. Recombinant FSH was started at 225-300 IU/day, and hMG was added when clinically indicated. Final oocyte maturation was triggered with a single dose of recombinant hCG, and OPU was performed 36 hours later.
Retrieval technique. Both centres used 17-gauge Wallace® needles (CooperSurgical, Trumbull, CT, USA) under transabdominal ultrasound guidance, with a constant aspiration pressure of 140 mmHg.
Direct aspiration: each follicle was aspirated once with a single-lumen needle and was not flushed.
Follicular flushing: a double-lumen needle was used. If a follicle yielded no COC on the first aspiration, it was flushed with 3 mL of pre-warmed (37 °C) culture medium and aspirated again. This was repeated until a COC was found or six flushes had been done.
Laboratory handling. Embryologists assessed the COCs immediately after retrieval. After denudation, oocytes were classified by nuclear maturity as metaphase II (MII), metaphase I (MI), germinal vesicle (GV) or degenerated. MII oocytes were vitrified following each laboratory's validated standard operating procedures.
Patient preference documentation. Before retrieval, every patient filled in a standard intake form stating her preferred retrieval route (transabdominal or transvaginal). These forms were collected as part of routine care.
Statistical analysis. Normality was tested with the Shapiro-Wilk test. Continuous variables were compared with Welch's t-test or the Mann-Whitney U test, as appropriate. Categorical variables were compared with the chi-square test or Fisher's exact test. Two-sided P < 0.05 was taken as significant. Analyses were run in Python 3.11 (SciPy 1.11, pandas 2.0).
Potential sources of bias. Technique was confounded with centre and operator. The groups also differed in stimulation protocol mix (PPOS was used more at Centre B), so differences in stimulation duration and progesterone levels are expected. Embryology laboratories were not standardised between centres.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 6 Months
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Direct Aspiration | – | –Women with diminished ovarian reserve (AMH ≤1.0 ng/mL) undergoing transabdominal ultrasound-guided oocyte retrieval for oocyte cryopreservation at Centre A (İstanbul). One operator performs every retrieval with a 17-gauge single-lumen needle at a constant aspiration pressure of 140 mmHg. Each follicle is aspirated once and is not flushed. Direct aspiration is the centre's routine retrieval technique. |
| Follicular Flushing | – | –Women with diminished ovarian reserve (AMH ≤1.0 ng/mL) undergoing transabdominal ultrasound-guided oocyte retrieval for oocyte cryopreservation at Centre B (Ankara). One operator performs every retrieval with a 17-gauge double-lumen needle at a constant aspiration pressure of 140 mmHg. When the first aspiration of a follicle yields no cumulus-oocyte complex, the follicle is flushed with 3 mL of pre-warmed (37 °C) culture medium and aspirated again. This is repeated until a complex is recovered, up to six flushes. Follicular flushing is the centre's routine retrieval technique. |
Who may qualify
- Ages
- 18 to 42 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- Consecutive women aged 18-42 years with diminished ovarian reserve (serum AMH ≤1.0 ng/mL) who are undergoing oocyte cryopreservation for fertility preservation at two IVF centres in Turkey (Ankara and İstanbul). All of them decline transvaginal access for cultural or personal reasons and undergo transabdominal ultrasound-guided oocyte retrieval. Women who receive direct aspiration at one centre are compared with women who receive follicular flushing at the other, as each centre's routine retrieval technique.
Key inclusion criteria (7 listed)
- Women aged 18-42 years
- Serum anti-Müllerian hormone (AMH) ≤1.0 ng/mL
- Planned oocyte cryopreservation for fertility preservation
- Decline of transvaginal oocyte retrieval for cultural or personal reasons, with transabdominal retrieval chosen as the preferred route
- Eligible for oocyte cryopreservation under Turkish regulations
Key exclusion criteria (7 listed)
- Conditions that prevent safe transabdominal access, such as extensive pelvic adhesions or unfavourable ovarian position
- Previous major abdominal or pelvic surgery likely to interfere with the procedure
- Active pelvic infection
- Suspected ovarian malignancy
- Contraindications to sedation or oocyte retrieval
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Number of Metaphase II (MII) Oocytes Retrieved per Participant
Time frame: Day of oocyte retrieval (assessed within 2 hours after retrieval)
The number of mature oocytes per participant. After denudation, embryologists classify each retrieved oocyte by nuclear maturity, and those with a visible first polar body are counted as MII.
2 secondary outcomes
Follicle-to-Oocyte Index (FOI)
Time frame: From start of ovarian stimulation to day of oocyte retrieval (approximately 2 weeks)
Oocyte Maturation Rate
Time frame: Day of oocyte retrieval
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be made publicly available. The study population is small and culturally sensitive (unmarried women undergoing transabdominal oocyte retrieval for fertility preservation), and participants were not asked to consent to public data sharing. Releasing individual-level data could therefore risk re-identification. Under Turkish personal data protection law (KVKK, Law No. 6698), health data are a special category of personal data with restricted transfer. De-identified aggregate data underlying the published results may be made available by the corresponding author on reasonable request, subject to approval by the institutional ethics committees and a data-sharing agreement.
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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.
Emre G pabuçcu, Prof. study director
Ufuk University School of Medicine
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Fertility Preservation, run by Centrum Clinic IVF Center at 2 sites in Turkey (Türkiye).
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 7 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Turkey (Türkiye). 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Emre pabuçcu, Professor (05324147844, emregpabuccu@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Metaphase II (MII) Oocytes Retrieved per Participant (time frame: Day of oocyte retrieval (assessed within 2 hours after retrieval)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 20 Oct 2026.