The review found no eligible studies for this question.
Progesterone showed no clear difference in live birth/ongoing pregnancy rate 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).
Progesterone may leads to higher clinical pregnancy per woman 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 showed no clear difference in multiple pregnancy per woman compared with no treatment or placebo (route of progesterone administration) (low certainty).
The review found no eligible studies for this question.
The review found no eligible studies for this question.
It is very uncertain whether oral progesterone changes ongoing pregnancy rate compared with vaginal progesterone (very low certainty).
It is very uncertain whether oral progesterone changes miscarriage rate per clinical pregnancy compared with vaginal progesterone (very low certainty).
It is very uncertain whether oral progesterone changes clinical pregnancy rate compared with vaginal progesterone (very low certainty).
The review found no eligible studies for this question.
The review found no eligible studies for this question.
It is very uncertain whether vaginal progesterone changes clinical pregnancy rate compared with gonadotropin‐releasing hormone (GnRH) agonist (very low certainty).
It is very uncertain whether 300 mg vaginal progesterone changes ongoing pregnancy rate compared with 600 mg vaginal progesterone (very low certainty).
It is very uncertain whether 300 mg vaginal progesterone changes multiple pregnancy rate compared with 600 mg vaginal progesterone (very low certainty).
The review found no eligible studies for this question.
It is very uncertain whether intramuscular (IM) progesterone changes ongoing pregnancy rate compared with vaginal progesterone (very 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 intramuscular (IM) progesterone changes clinical pregnancy rate compared with vaginal progesterone (very low certainty).