Progesterone showed no clear difference in clinical pregnancy compared with progesterone + oestrogen (low certainty).
Progesterone may leads to lower clinical pregnancy compared with progesterone + GnRH agonist (low certainty).
Progesterone may leads to higher clinical pregnancy per woman compared with no treatment or placebo (route of progesterone administration) (low certainty).
Progesterone showed no clear difference in miscarriage per clinical pregnancy compared with no treatment or placebo (route of progesterone administration) (low certainty).
It is very uncertain whether progesterone changes clinical pregnancy per woman ‐ oral route compared with no treatment or placebo (route of progesterone administration) (very low certainty).
Progesterone may leads to higher clinical pregnancy compared with placebo/no treatment (low certainty).
Progesterone may leads to higher clinical pregnancy compared with placebo/no treatment (low certainty).
Progesterone showed no clear difference in clinical pregnancy compared with hCG regimens (moderate certainty).
It is very uncertain whether oral progesterone changes clinical pregnancy rate compared with vaginal progesterone (very low certainty).
Progesterone may leads to higher clinical pregnancy rate compared with placebo/no treatment (low certainty).
Progesterone may leads to higher clinical pregnancy rate compared with placebo/no treatment (low certainty).
It is very uncertain whether oral progesterone changes miscarriage rate per clinical pregnancy compared with vaginal progesterone (very low certainty).
Progesterone showed no clear difference in miscarriage rate per clinical pregnancy compared with placebo/no treatment (low certainty).
Progesterone showed no clear difference in miscarriage rate per clinical pregnancy compared with placebo/no treatment (low certainty).
Progesterone showed no clear difference in miscarriage rate per clinical pregnancy compared with placebo/no treatment (low certainty).
It is very uncertain whether intramuscular (IM) progesterone changes clinical pregnancy rate compared with vaginal progesterone (very low certainty).
It is very uncertain whether aqueous subcutaneous (Sc) progesterone changes clinical pregnancy rate compared with vaginal progesterone gel (very low certainty).
It is very uncertain whether vaginal progesterone changes clinical pregnancy rate compared with gonadotropin‐releasing hormone (GnRH) agonist (very low certainty).