The patients will undergo standard assisted conception procedures; controlled ovarian stimulation (COS), oocyte pickup procedure (OPU), ICSI, embryo culture, blastocyst vitrification and frozen embryo transfer. If sufficient (>2) viable blastocyst develop from the in vitro culture of their embryos, all viable blastocysts will be cryopreserved using a routine vitrification procedure. This is the eligible patient population. On the day the last blastocyst(s) are frozen the patients will be given a further opportunity to ask questions and if satisfied they will be asked to complete a trial consent. At this point patients will be randomized by numeric code and given a schedule and drug prescription for scheduling the start of their hormone supplemented frozen embryo transfer cycle. During the scheduling period the patients will follow the drug prescription provided . After the completion of their treatment - the transfer of one or two vitrified-warmed blastocyst - the patients from both groups will receive identical luteal support drug schedules and prescriptions. A blood test will be performed on the 15th day of progesterone supplementation, to determine the βhCG blood concentration. Currently at Antalya IVF, approximately 75% of patients who have blastocysts transferred in a frozen embryo transfer cycle have a positive biochemical pregnancy test, >29 international units per litre (IU/L) of human chorionic gonadotropin (βhCG). If pregnant, patients will continue using estrogen and progesterone supplementation for a further 8 weeks. At 7 weeks of gestation (5 weeks after embryo transfer ) the patients will receive a transvaginal ultrasound scan (TVUS) to check for pregnancy viability (fetal sac with cardiac activity). Thereafter the patients will have regular TVUS to follow fetal development. At 20 weeks of gestation a TVUS will be performed to confirm an ongoing pregnancy (normal fetal development).