Embryo Culture Under Constant 5% vs Gradient 8%, 5%, 2% Oxygen Concentration

Embryonic Development Clinical Trial

Official title:

The Effect of Constant 5% Versus Gradient 8%, 5%, 2% Oxygen Concentration on the Development of Sibling Human Embryos in Vitro

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT05898178
• Other study ID #: 0120-405/2021/4
• Secondary ID: P3-0327
• Status: Completed
• Phase: N/A
• Start date: January 1, 2022
• Est. completion date: January 1, 2023

Study information

• Verified date: May 2023
• Source: University Medical Centre Maribor
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to investigate the development of human embryos in vitro under two different oxygen concentrations; a static 5% during all five days of culture or under an oxygen gradient, starting with 8% from day-0 to day-3, continuing with 5% on day-3 and following with 2% of oxygen from the end of day-3 to day-5.

Description:

Several studies have shown that embryonic morphological parameters improved when the oxygen concentration in embryo culture was reduced from 20% to 5%. Early mammalian embryos developed faster, had shorter cell cycles, a higher blastocyst formation rate and a better integrity of the inner cell mass (ICM) compared to embryos cultured at 20% oxygen concentration.

Recent studies have shown that the oxygen concentration in the female reproductive tract is not static. In the fallopian tubes of higher mammals it is at around 8%, while in the uterus, at the time of embryo implantation, the oxygen concentration is almost anoxic (2%).

Mimicking such physiological conditions that better reflect the in vivo environment in the human reproductive tract is the goal of assisted reproductive technology (ART).

The aim of this study is to assess whether changing the static 5% oxygen during five days of in vitro embryo culture to the gradient of oxygen, starting with 8% from day-0 to day-3, continuing with 5% on day-3 and following with 2% of oxygen from the end of day-3 to day-5, better reflects conditions found within the human reproductive tract and improves embryo developmental characteristics.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 44
• Est. completion date: January 1, 2023
• Est. primary completion date: January 1, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Female
• Age group: 18 Years to 35 Years

Eligibility

Inclusion Criteria:

• Age of women between 18 and 35 years.

• Body mass index (BMI) between 18 and 30 kg/m².

• Only patients with ICSI procedure (male factor of infertility, excluding azoospermia) and blastocyst culture.

• Patients from first and second ICSI cycle attempt.

• Gonadotropin hormone-releasing hormone (GnRH) antagonist cycles.

Exclusion Criteria:

• Presence of endometriosis.

• Previous clinical intervention on ovaries.

• Connected endocrine or metabolic diseases.

• Presence of polycystic ovary syndrome.

Related Conditions & MeSH terms

• Embryo Morphokinetics
• Embryonic Development

Intervention

Other:
• Experimental intervention: 8-5-2% oxygen gradient concentration in the incubator
After oocyte retrieval and insemination, half of a given patient's embryos will be randomly allocated in an incubator set at a gradient of oxygen tension (8-5-2%). The embryos will remain in the incubator until their developmental assessments on day 5.

Locations

Country	Name	City	State
Slovenia	University Medical Centre Maribor	Maribor

Sponsors (1)

Lead Sponsor	Collaborator
University Medical Centre Maribor

Country where clinical trial is conducted

Slovenia, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Proportion of inseminated oocytes developed to the morphologically optimal blastocysts on day 5	The primary outcome measure will be the proportion of oocytes that will develop to the morphologically optimal day-5 blastocysts, scored 4-5AA according to Gardner criteria. According to the scoring system of Gardner, blastocyst morphology parameters such as the degree of blastocoel expansion (1-5), the morphological appearance of the inner cell mass (ICM) (A, B, C) and the cohesiveness of trophectoderm (TE) (A, B, C) will be measured.	Embryos will be annotated on day 5 post insemination (at 8:00 am).
Secondary	Measured times from insemination to different embryonic stages reached	Using the time-lapse software, videos will be reviewed directly by manually advancing the images frame by frame. Thus morphokinetic timings such as: t2 - time to 2-cell stage, t3 - time to 3-cell stage, t4 - time to 4-cell stage, t5- time to 5-cell stage, t6 - time to 6-cell stage, t7 - time to 7-cell stage, t8 - time to 8-cell stage, tSC - time to start of compaction, tM - time to completion of morula, tSB - time to initiation of blastulation, tEB - time to initiation of expansion, tB - time to full blastocyst, will be recorded for each embryo.	: Morphokinetic timings will be recorded continuously (a picture will be taken every 5 minutes) during 5 days of embryo culture.
Secondary	Blastocyst and inner cell mass (ICM) surface area measurement on day 5	Surface measurements of blastocysts and inner cell mass (ICM) will be recorded on time-lapse photos at 116 hours after insemination. The surfaces will be measured in square micrometres using the Primo vision software's measuring tool. An ellipse will be generated around the trophectoderm's outer edge or the inner cell mass. These measurements will exclude the zona pellucida. The measurements will be taken at the focus plane with the largest surface area.	Fix time (116 hours) post insemination
Secondary	Number of trophectoderm cells on day 5	At 116 hours following insemination, the number of trophectoderm cells will be counted using time-lapse photos. Images will be focused on the trophectoderm's outermost edge to better determine the boundaries of each individual cell.	Fix time (116 hours) post insemination.
Secondary	Incidence of atypical embryo cleavages	Time-lapse videos for each embryo will be reviewed for atypical cleavage features, such as; pseudofurrows, direct cleavage, reverse cleavage, multinucleation, irregular chaotic division, cell exclusion and blastocyst collapse, using Primo vision software by manually forwarding the images frame by frame. The frequency of abnormal cleavage patterns will be recorded.	Continuously (a picture will be taken every 5 minutes) during 5 days of embryo culture.