Comparison of day 5 and day 6 embryo transfers for slow growing embryos for in vitro fertilisation (IVF) treatment

When is the best time to replace slow developing embryos? A comparison between day 5 and day 6 transfers: a randomised controlled trial

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN90191687

Enrollment

100

Registered

2012-12-27

Start date

2013-02-01

Completion date

Unknown

Last updated

2018-07-30

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

Conditions

Subfertility patients undergoing IVF / ICSI treatment Urological and Genital Diseases Female infertility, unspecified

Interventions

All participants will follow the routine IVF/ICSI protocol till the day of embryo transfer. Following this they will be allocated to either of the two study arms. Study arm 1: patient to have embryo

Eligibility

Sex/Gender

Female

Inclusion criteria

Inclusion criteria: Women age 21-45 undergoing a single IVF / Intra-cytoplasmic sperm injection (ICSI) treatment with their own oocytes during the specified study duration who: 1. Proceed to have a day 5 transfer 2. Have no fast developing embryos for transfer on day 5

Exclusion criteria

Exclusion criteria: Women who have already participated in the study for a previous cycle

Design outcomes

Primary

Measure	Time frame
Clinical pregnancy rate	—

Secondary

Measure	Time frame
Delayed blastocyst conversion rate	—

Countries

United Kingdom

Outcome results

None listed

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