Fertility IssuesNCT07050537
A Multicenter Prospective Randomized Controlled Clinical Trial Comparing Constant (5%) Versus Sequential (5%-2%) Oxygen Concentration Embryo Culture Protocols in Assisted Reproductive Technology
A study testing Constant oxygen concentration protocols in embryo culture and Sequential oxygen concentration protocols in embryo culture in people with Fertility Issues and Blastocyst IVF, run by The First Affiliated Hospital with Nanjing Medical University at 6 sites in China.
Trial summary
To evaluate whether there were significant differences in the effects of constant (5%) versus sequential (5%-2%) oxygen concentration protocols in embryo culture on term live birth rates. Read more about this study
- Who is it for?
- Ages 20 to 40 years, women only
- Conditions the study is for
- Fertility Issues, Blastocyst IVF, Embryo Culture
- What is being tested?
- Constant oxygen concentration protocols in embryo culture and Sequential oxygen concentration protocols in embryo culture
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 980 participants
- Where
- 6 sitesChina
- Study dates
- 1 Mar 2025to 31 Aug 2027
- Phase
- Interventional
- 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 20 to 40 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Female: age ≥20 and ≤40 years, male: age ≥20 and ≤50 years;
- Proposed 1st or 2nd cycle of IVF or ICSI fertilization;
- ≥ 4 transferable embryos at oocyte stage.
Who cannot join
- Diagnosis of abnormal uterine cavity morphology (confirmed by 3D ultrasound or hysteroscopy), including uterine malformations (mediastinal uterus, unicornuate uterus, bicornuate uterus), submucosal uterine fibroids, or uterine adhesions;
- Patients who are proposed to undergo IVM;
- Patients who are proposed to undergo PGD/ PGS;
- Patients with untreated severe hydrosalpinx (confirmed by ultrasound or HSG);
- Patients with a history of recurrent miscarriage (2 or more previous pregnancy losses, excluding biochemical pregnancies);
- Patients who plan to freeze whole embryos and are unable to complete a single embryo transfer within six months;
- Patients with contraindications to assisted reproductive technology and pregnancy, or suffering from diseases that have a definite effect on pregnancy: including uncontrolled hypertension, heart disease with definite symptoms, uncontrolled diabetes, undefined diagnosis of liver or kidney disease or liver or kidney insufficiency, severe anemia, history of previous venous thrombosis, pulmonary embolism or cerebrovascular events, history of malignant tumors, suspected malignant tumors, and undiagnosed abnormal uterine bleeding.
Trial locations and contacts
6 sites in 1 country. Contact the study team or a site near you to ask about taking part.
6 sites in 1 country
China6 sites, 6 recruiting
- Recruiting
Changzhou Maternal And Child Health Care Hospital
Changzhou, Jiangsu, 213000
Xiyang Xia, MD, +86 13861266074, xiaxiyang900711@163.com
- Recruiting
Nanjing Women and Children's Healthcare Hospital
Nanjing, Jiangsu, 210000
Mengqian Chen, MD, +86 15105183515, imchenmx@163.com
- Recruiting
Reproductive Medicine of First Affiliated Hospital with Nanjing Medical University
Nanjing, Jiangsu
Xiang Ma, MD. PHD, +86 18001581878, sxmaxiang@126.com
Haofeng Wang, +86 18018387209, haofengwang@stu.njmu.edu.cn
- Recruiting
Suzhou Municipal Hospital
Suzhou, Jiangsu
Aiyan Zheng, MD, +86 18662180810, 36663735@qq.com
- Recruiting
Northwest Women's and Children's Hospital
Xi’an, Shanxi, 710000
Tingting He, 18392161661, 1016760162@qq.com
- Recruiting
The Third Affiliated Hospital of Zhengzhou University
Zhengzhou, Henan, 450000
Binnan Ren, MD, +86 13253619382, moking_rbn@163.com
About this study
Official title: A Multicenter Prospective Randomized Controlled Clinical Trial Comparing Constant (5%) Versus Sequential (5%-2%) Oxygen Concentration Embryo Culture Protocols in Assisted Reproductive Technology: Evaluating Term Live Birth and Offspring Health Outcomes
To evaluate whether there were significant differences in the effects of constant (5%) versus sequential (5%-2%) oxygen concentration protocols in embryo culture on term live birth rates.
This study will be conducted in five centers including the Clinical Center of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical Universit. 980 women who wish to undergo blastocyst transplantation will be included in the study.
The study data will be analyzed statistically.
Read the detailed description
While blastocyst transfer has been shown to improve live birth rates, concerns exist regarding potential telomere shortening in offspring, which is associated with premature aging and various health issues. Our previous study further explores the role of oxygen tension in telomere length regulation, identifying hypoxia-inducible factor 1α (Hif1α) degradation as a key factor. Based on these findings, the study proposes a prospective, randomized controlled clinical trial comparing constant (5%) versus sequential (5%-2%) oxygen concentration protocols in embryo culture to assess their impact on term live birth rates and offspring telomere length.
This study will be conducted in five centers including the Clinical Center of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical Universit. 980 women who wish to undergo blastocyst transplantation will be included in the study.
Female infertile patients who consent to blastocyst transfer will be considered for inclusion in the study. Patients will be randomly assigned to a constant (5%) or sequential (5%-2%) oxygen concentration protocols in embryo culture. This study will record live birth rates, perinatal and perinatal complications, and offspring health status of women in both groups of embryo culture regimens to assess the effects of different embryo culture regimens on term live birth rates and offspring health.
- Conditions
- Fertility Issues, Blastocyst IVF, Embryo Culture
- Being tested
- Constant oxygen concentration protocols in embryo culture, Sequential oxygen concentration protocols in embryo culture
- Keywords
- Blastocyst IVF, Fertility
- Medical subject headings
- Infertility
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Constant oxygen concentration protocols in embryo cultureProcedure or surgery
Participants were randomly assigned to constant (5%) oxygen concentration group and received different blastocyst culture protocols.
Sequential oxygen concentration protocols in embryo cultureProcedure or surgery
Participants were randomly assigned to sequential (5%-2%) oxygen concentration group and received different blastocyst culture protocols.
| Study group | Role | What they receive |
|---|---|---|
| Constant (5%) oxygen concentration protocols in embryo culture | Placebo comparator | Patients randomly assigned to use constant (5%) oxygen concentration protocols in embryo culture Receives: Procedure: Constant oxygen concentration protocols in embryo culture |
| Sequential (5%-2%) oxygen concentration protocols in embryo culture | Experimental | Patients randomly assigned to use Sequential (5%-2%) oxygen concentration protocols in embryo culture Receives: Procedure: Sequential oxygen concentration protocols in embryo culture |
What is being measured
The primary outcome is the main question the study is designed to answer.
Term live births
Full-term healthy live birth rate for all patients
Measured: 3 years
Secondary outcomes (5)
Offspring health (Peripheral blood telomere length)
Peripheral blood telomere length in all live-born offspring
Measured: 3 years
Clinical pregnancy rate
Clinical pregnancy rate for all transfer cycles
Measured: 3 years
Ectopic pregnancy rate
Ectopic pregnancy rate for all transfer cycles
Measured: 3 years
Implantation rate
Implantation rate per transfer cycle
Measured: 3 years
Miscarriage rate
Miscarriage rate per transfer cycle
Measured: 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jul 2025
- Study start1 Mar 2025
- Primary completion31 Mar 2027 (estimated)
- Study completion31 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for Fertility IssuesStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 980 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The First Affiliated Hospital with Nanjing Medical University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07050537
- Sponsor's protocol ID
- RCT-ECP
- Status last verified
- Jun 2025
- First submitted
- 26 Jun 2025
- Last updated
- 1 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
De Munck N, Janssens R, Segers I, Tournaye H, Van de Velde H, Verheyen G. Influence of ultra-low oxygen (2%) tension on in-vitro human embryo development. Hum Reprod. 2019 Feb 1;34(2):228-234. doi: 10.1093/humrep/dey370.
PubMed 30576441Kaser DJ, Bogale B, Sarda V, Farland LV, Williams PL, Racowsky C. Randomized controlled trial of low (5%) versus ultralow (2%) oxygen for extended culture using bipronucleate and tripronucleate human preimplantation embryos. Fertil Steril. 2018 Jun;109(6):1030-1037.e2. doi: 10.1016/j.fertnstert.2018.02.119.
PubMed 29935641Brouillet S, Baron C, Barry F, Andreeva A, Haouzi D, Gala A, Ferrieres-Hoa A, Loup V, Anahory T, Ranisavljevic N, Gaspari L, Hamamah S. Biphasic (5-2%) oxygen concentration strategy significantly improves the usable blastocyst and cumulative live birth rates in in vitro fertilization. Sci Rep. 2021 Nov 17;11(1):22461. doi: 10.1038/s41598-021-01782-6.
PubMed 34789773Chakravarti D, LaBella KA, DePinho RA. Telomeres: history, health, and hallmarks of aging. Cell. 2021 Jan 21;184(2):306-322. doi: 10.1016/j.cell.2020.12.028. Epub 2021 Jan 14.
PubMed 33450206Lopez-Otin C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023 Jan 19;186(2):243-278. doi: 10.1016/j.cell.2022.11.001. Epub 2023 Jan 3.
PubMed 36599349Wang C, Gu Y, Zhou J, Zang J, Ling X, Li H, Hu L, Xu B, Zhang B, Qin N, Lv H, Duan W, Jiang Y, He Y, Jiang T, Chen C, Han X, Zhou K, Xu B, Liu X, Tao S, Jiang Y, Du J, Dai J, Diao F, Lu C, Guo X, Huo R, Liu J, Lin Y, Xia Y, Jin G, Ma H, Shen H, Hu Z. Leukocyte telomere length in children born following blastocyst-stage embryo transfer. Nat Med. 2022 Dec;28(12):2646-2653. doi: 10.1038/s41591-022-02108-3. Epub 2022 Dec 15.
PubMed 36522605
Study at a glance
From the registry record, last updated by the sponsor on 1 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Multicenter Prospective Randomized Controlled Clinical Trial Comparing Constant (5%) Versus Sequential (5%-2%) Oxygen Concentration Embryo Culture Protocols in Assisted Reproductive Technology: Evaluating Term Live Birth and Offspring Health Outcomes
- ClinicalTrials.gov ID
- NCT07050537
- Acronym / sponsor ID
- RCT-ECP
- Conditions
- Fertility Issues, Blastocyst IVF, Embryo Culture
- Keywords
- Blastocyst IVF, Fertility
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 980 participants (estimated)
- Lead sponsor
- The First Affiliated Hospital with Nanjing Medical UniversityUniversity, hospital or other
- Study start
- 1 Mar 2025 (actual)
- Primary completion
- 31 Mar 2027 (estimated)
- Study completion
- 31 Aug 2027 (estimated)
- First posted
- 3 Jul 2025 (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.
To evaluate whether there were significant differences in the effects of constant (5%) versus sequential (5%-2%) oxygen concentration protocols in embryo culture on term live birth rates.
This study will be conducted in five centers including the Clinical Center of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical Universit. 980 women who wish to undergo blastocyst transplantation will be included in the study.
The study data will be analyzed statistically.
Detailed description
While blastocyst transfer has been shown to improve live birth rates, concerns exist regarding potential telomere shortening in offspring, which is associated with premature aging and various health issues. Our previous study further explores the role of oxygen tension in telomere length regulation, identifying hypoxia-inducible factor 1α (Hif1α) degradation as a key factor. Based on these findings, the study proposes a prospective, randomized controlled clinical trial comparing constant (5%) versus sequential (5%-2%) oxygen concentration protocols in embryo culture to assess their impact on term live birth rates and offspring telomere length.
This study will be conducted in five centers including the Clinical Center of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical Universit. 980 women who wish to undergo blastocyst transplantation will be included in the study.
Female infertile patients who consent to blastocyst transfer will be considered for inclusion in the study. Patients will be randomly assigned to a constant (5%) or sequential (5%-2%) oxygen concentration protocols in embryo culture. This study will record live birth rates, perinatal and perinatal complications, and offspring health status of women in both groups of embryo culture regimens to assess the effects of different embryo culture regimens on term live birth rates and offspring health.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Constant (5%) oxygen concentration protocols in embryo culture | Placebo comparator | Procedure: Constant oxygen concentration protocols in embryo culturePatients randomly assigned to use constant (5%) oxygen concentration protocols in embryo culture |
| Sequential (5%-2%) oxygen concentration protocols in embryo culture | Experimental | Procedure: Sequential oxygen concentration protocols in embryo culturePatients randomly assigned to use Sequential (5%-2%) oxygen concentration protocols in embryo culture |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Female: age ≥20 and ≤40 years, male: age ≥20 and ≤50 years;
- Proposed 1st or 2nd cycle of IVF or ICSI fertilization;
- ≥ 4 transferable embryos at oocyte stage.
Key exclusion criteria (7 listed)
- Diagnosis of abnormal uterine cavity morphology (confirmed by 3D ultrasound or hysteroscopy), including uterine malformations (mediastinal uterus, unicornuate uterus, bicornuate uterus), submucosal uterine fibroids, or uterine adhesions;
- Patients who are proposed to undergo IVM;
- Patients who are proposed to undergo PGD/ PGS;
- Patients with untreated severe hydrosalpinx (confirmed by ultrasound or HSG);
- Patients with a history of recurrent miscarriage (2 or more previous pregnancy losses, excluding biochemical pregnancies);
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 |
|---|---|---|
| Constant oxygen concentration protocols in embryo cultureParticipants were randomly assigned to constant (5%) oxygen concentration group and received different blastocyst culture protocols. | Procedure or surgery | Constant (5%) oxygen concentration protocols in embryo culture |
| Sequential oxygen concentration protocols in embryo cultureParticipants were randomly assigned to sequential (5%-2%) oxygen concentration group and received different blastocyst culture protocols. | Procedure or surgery | Sequential (5%-2%) oxygen concentration protocols in embryo culture |
Primary outcome
Term live births
Time frame: 3 years
Full-term healthy live birth rate for all patients
5 secondary outcomes
Offspring health (Peripheral blood telomere length)
Time frame: 3 years
Clinical pregnancy rate
Time frame: 3 years
Ectopic pregnancy rate
Time frame: 3 years
Implantation rate
Time frame: 3 years
Miscarriage rate
Time frame: 3 years
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 1 Jun 2026.
- Background: PubMed 30576441De Munck N, Janssens R, Segers I, Tournaye H, Van de Velde H, Verheyen G. Influence of ultra-low oxygen (2%) tension on in-vitro human embryo development. Hum Reprod. 2019 Feb 1;34(2):228-234. doi: 10.1093/humrep/dey370.
- Background: PubMed 29935641Kaser DJ, Bogale B, Sarda V, Farland LV, Williams PL, Racowsky C. Randomized controlled trial of low (5%) versus ultralow (2%) oxygen for extended culture using bipronucleate and tripronucleate human preimplantation embryos. Fertil Steril. 2018 Jun;109(6):1030-1037.e2. doi: 10.1016/j.fertnstert.2018.02.119.
- Background: PubMed 34789773Brouillet S, Baron C, Barry F, Andreeva A, Haouzi D, Gala A, Ferrieres-Hoa A, Loup V, Anahory T, Ranisavljevic N, Gaspari L, Hamamah S. Biphasic (5-2%) oxygen concentration strategy significantly improves the usable blastocyst and cumulative live birth rates in in vitro fertilization. Sci Rep. 2021 Nov 17;11(1):22461. doi: 10.1038/s41598-021-01782-6.
- Background: PubMed 33450206Chakravarti D, LaBella KA, DePinho RA. Telomeres: history, health, and hallmarks of aging. Cell. 2021 Jan 21;184(2):306-322. doi: 10.1016/j.cell.2020.12.028. Epub 2021 Jan 14.
- Background: PubMed 36599349Lopez-Otin C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023 Jan 19;186(2):243-278. doi: 10.1016/j.cell.2022.11.001. Epub 2023 Jan 3.
- Background: PubMed 36522605Wang C, Gu Y, Zhou J, Zang J, Ling X, Li H, Hu L, Xu B, Zhang B, Qin N, Lv H, Duan W, Jiang Y, He Y, Jiang T, Chen C, Han X, Zhou K, Xu B, Liu X, Tao S, Jiang Y, Du J, Dai J, Diao F, Lu C, Guo X, Huo R, Liu J, Lin Y, Xia Y, Jin G, Ma H, Shen H, Hu Z. Leukocyte telomere length in children born following blastocyst-stage embryo transfer. Nat Med. 2022 Dec;28(12):2646-2653. doi: 10.1038/s41591-022-02108-3. Epub 2022 Dec 15.
- Individual participant dataSharing planned: No
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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.
6 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Constant oxygen concentration protocols in embryo culture and Sequential oxygen concentration protocols in embryo culture in people with Fertility Issues and Blastocyst IVF, run by The First Affiliated Hospital with Nanjing Medical University at 6 sites in China.
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 3 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 1 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in China. 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. Some participants in this study may receive a placebo. 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 Xiang Ma (+86 18001581878, sxmaxiang@126.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Term live births (time frame: 3 years). 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 NCT07050537, which also lists 6 linked publications.
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 1 Jun 2026.