The review found no eligible studies for this question.
Blastocyst‐stage may leads to higher live birth rate per fresh transfer compared with cleavage‐stage embryo transfer (low certainty).
Blastocyst‐stage may leads to lower cumulative pregnancy rate (slow freezing) compared with cleavage‐stage embryo transfer (low certainty).
Blastocyst‐stage probably leads to higher cumulative pregnancy rate (vitrification) compared with cleavage‐stage embryo transfer (moderate certainty).
Blastocyst‐stage probably leads to higher clinical pregnancy rate compared with cleavage‐stage embryo transfer (moderate certainty).
Blastocyst‐stage showed no clear difference in multiple pregnancy rate compared with cleavage‐stage embryo transfer (low certainty).
Blastocyst‐stage showed no clear difference in miscarriage rate compared with cleavage‐stage embryo transfer (low certainty).
Blastocyst‐stage may leads to lower embryo freezing rate compared with cleavage‐stage embryo transfer (low certainty).
Blastocyst‐stage probably leads to higher failure rate to transfer any embryos compared with cleavage‐stage embryo transfer (moderate certainty).