Cryopreservation of human embryos in a modified cryoprotectant solution

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN93314892

Enrollment

200

Registered

2007-02-01

Start date

2003-05-01

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 (IVF) and Intra-Cytoplasmic Sperm Injection (ICSI) Pregnancy and Childbirth Fertilisation

Interventions

Freezing the embryos in a solution containing 0.3M sucrose.

Eligibility

Sex/Gender

Female

Inclusion criteria

Inclusion criteria: 1. In Vitro Fertilisation (IVF) and Intra-Cytoplasmic Sperm Injection (ICSI) patients - new patients and returning patients who were not previously approached for the trial 2. Patients using donor sperm if donor consented to research 3. Patients who consented but did not have sufficient embryos to enter the trial may be approached in a later cycle (re-consent needed)

Exclusion criteria

Exclusion criteria: 1. Women in ECoSSE trial (see ISRCTN86466058 for details of this trial) 2. Women with two or more previous cycles but no freezing 3. Women 38 or over with one previous cycle but no freezing 4. Recipients of eggs

Design outcomes

Primary

Measure	Time frame
Recovery of intact embryos after thawing: with 75 patients having embryos thawed in each arm, the study has a 90% power at 5% level of significance of detecting a 25% increase in the proportion of women with at least two intact embryos after thawing the whole cohort. Since some patients may not return for thawing for several years we estimate that we need to freeze for at least 100 patients in each arm. We allowed two years to recruit and freeze, plus a further two years for sufficient thawing. We hope that a later follow up will also be possible.	—

Measure

Time frame

Recovery of intact embryos after thawing: with 75 patients having embryos thawed in each arm, the study has a 90% power at 5% level of significance of detecting a 25% increase in the proportion of women with at least two intact embryos after thawing the whole cohort. Since some patients may not return for thawing for several years we estimate that we need to freeze for at least 100 patients in each arm. We allowed two years to recruit and freeze, plus a further two years for sufficient thawing. We hope that a later follow up will also be possible.

—

Secondary

Measure	Time frame
1. Implantation rate 2. Miscarriage 3. Live birth Sample size will not allow statement of significant differences.	—

Countries

United Kingdom

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Mar 29, 2026