NCT03548532.

Trial name or title	Embryo culture at a constant temperature of 36.6°C or 37.1°C: A randomised controlled trial
Methods	Randomised controlled trial
Participants	Universitair Ziekenhuis Brussel, Belgium Inclusion criteria Day 5 transfer Single embryo transfer Only ejaculated sperm (fresh or frozen, autologous or heterologous) BMI < 35 Age < 40 years Cycle rank < 3 for current child Last ultrasound: 8 follicles of at least 12 mm At least 6 mature oocytes Exclusion criteria IVF IVF versus ICSI Failed fertilisation in previous cycle No previous cycle without embryo transfer No use of Ca ionophores for embryo quality or fertilisation problems
Interventions	Embryo culture in G210 incubator at 36.6°C versus 37.1°C
Outcomes	Primary: clinical pregnancy Secondary: fertilisation rate, embryo development/utilisation rate, live birth rate of the fresh cycle, cumulative live birth rate per cycle
Starting date	1 November 2017
Contact information	Neelke de Munck, neelke.demunck@uzbrussel.be
Notes	Estimated completion date: 1 September 2019

BMI: body mass index
 ICSI: intracytoplasmic sperm injection
 IVF: in vitro fertilisation