Blastocyst‐stage showed no clear difference in miscarriage rate compared with cleavage‐stage embryo transfer (low certainty).
It is very uncertain whether intramuscular (IM) progesterone changes miscarriage rate compared with vaginal progesterone (very low certainty).
It is very uncertain whether subcutaneous (Sc) gonadotropin‐releasing hormone (GnRH) agonist changes miscarriage rate compared with placebo/no treatment (very low certainty).
It is very uncertain whether pentoxifylline changes miscarriage rate compared with placebo (very low certainty).
Dopamine agonist plus co‐intervention showed no clear difference in miscarriage rate compared with co‐intervention (low certainty).
Dopamine agonist showed no clear difference in miscarriage rate compared with other active intervention (low certainty).
Dopamine agonist showed no clear difference in miscarriage rate compared with placebo/no intervention (low certainty).
The review found no eligible studies for this question.
It is very uncertain whether transvaginal aspiration of hydrosalpingeal fluid changes miscarriage rate compared with laparoscopic salpingectomy (very low certainty).
The review found no eligible studies for this question.
Repeated single embryo transfer (mixed policies) showed no clear difference in miscarriage rate compared with multiple embryo transfer (low certainty).
Single showed no clear difference in miscarriage rate compared with multiple embryo transfer (low certainty).
It is very uncertain whether laparoscopic myomectomy changes miscarriage Rate compared with myomectomy by laparotomy or mini‐laparotomy (very low certainty).
It is very uncertain whether monopolar resectoscope changes miscarriage rate compared with bipolar resectoscope (very low certainty).
It is very uncertain whether natural cycle changes miscarriage rate compared with programmed cycle (very low certainty).
Transdermal oestrogens showed no clear difference in miscarriage rate compared with oral oestrogens (low certainty).
It is very uncertain whether starting administration of the progestogen earlier changes miscarriage Rate compared with starting administration of the progestogen later (very low certainty).
It is very uncertain whether stimulated cycle changes miscarriage rate compared with programmed (very low certainty).
GnRH agonists showed no clear difference in miscarriage rate compared with control (low certainty).
It is very uncertain whether among different GnRH agonists changes miscarriage rate compared with placebo (very low certainty).