NCT05898178

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

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

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (actual)
• Sponsor: University Medical Centre Maribor · Academic / Other
• Sex: Female
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

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.

Detailed 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.

Conditions

• Embryonic Development
• Embryo Morphokinetics
• Embryo Morphometry

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2022-01-01
• Primary completion: 2023-01-01
• Completion: 2023-01-01
• First posted: 2023-06-12
• Last updated: 2025-06-08
• Results posted: 2025-06-08

Locations

1 site across 1 country: Slovenia