Comparison of the cryopreservation method for day 3 embryos using slow freezing or vitrification

Randomised controlled trial comparing the implantation potential of a frozen-thawed cleavage-stage embryo cryopreserved using vitrification or slow freezing

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN16672665

Enrollment

306

Registered

2009-01-30

Start date

2008-12-01

Completion date

Unknown

Last updated

2015-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

In vitro fertilisation Pregnancy and Childbirth Fertilisation methods

Interventions

IVF patients will receive a frozen-thawed embryo that was frozen using the vitrification method or the standard slow freezing method.

Eligibility

Sex/Gender

Female

Inclusion criteria

Inclusion criteria: 1. Female aged less than 38 years 2. Patients with day 3 single or double embryo transfer and surplus embryos frozen 3. Cryopreservation criteria: 3.1. 6 - 7 cell embryos on day 3 with less than or equal to 20% fragmentation 3.2. Greater than or equal to 8 cell embryos on day 3 with less than or equal to 50% fragmentation 3.3. No multi-nucleated embryos

Exclusion criteria

Exclusion criteria: Patients with preimplantation genetic diagnosis treatment

Design outcomes

Primary

Measure	Time frame
Live birth rate per frozen-thawed embryo	—

Secondary

Measure	Time frame
1. Post-thaw survival of thawed embryos (the percentage of intact blastomeres on the total number of blastomeres present before freezing) 2. Post-thaw development of embryos after overnight culture 3. Implantation rate per transferred embryo 4. Ongoing pregnancy rate per thawing cycle 5. Live birth rate per transferred embryo	—

Countries

Belgium

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026