Metformin showed no clear difference in multiple pregnancy rate (per woman) compared with placebo co‐treatment (low certainty).
IUI in stimulated cycles showed no clear difference in multiple pregnancy rate per couple compared with TI (low certainty).
Day 3 showed no clear difference in multiple pregnancy rate per woman compared with day 2 embryo transfer following IVF or ICSI (moderate certainty).
It is very uncertain whether hCG changes multiple pregnancy rate per pregnancy compared with gnRH‐a (very low certainty).
It is very uncertain whether hCG changes multiple pregnancy rate per pregnancy compared with LH surge (very low certainty).
u‐hCG showed no clear difference in multiple pregnancy rate per pregnancy compared with r‐hCG (low certainty).
It is very uncertain whether glucocorticoid supplementation changes multiple pregnancy rate per woman/couple compared with placebo (very low certainty).
IVF showed no clear difference in multiple pregnancy rate per woman randomised compared with IUI + ovarian stimulation with gonadotropins or CC (low certainty).
The review found no eligible studies for this question.
It is very uncertain whether IVF changes multiple pregnancy rate per woman randomised compared with unstimulated IUI (very low certainty).
Assisted hatching may leads to higher multiple pregnancy rate per woman randomised compared with no assisted hatching (low certainty).