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).
It is very uncertain whether vaginal progesterone changes clinical pregnancy rate compared with gonadotropin‐releasing hormone (GnRH) agonist (very low certainty).
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.
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).
The review found no eligible studies for this question.
It is very uncertain whether intramuscular (IM) progesterone changes adverse events  compared with vaginal progesterone (very low certainty).
The review found no eligible studies for this question.
It is very uncertain whether aqueous subcutaneous (Sc) progesterone changes ongoing pregnancy rate compared with vaginal progesterone gel (very low certainty).
It is very uncertain whether aqueous subcutaneous (Sc) progesterone changes clinical pregnancy rate compared with vaginal progesterone gel (very low certainty).
Levonorgestrel‐releasing intrauterine system (LNG‐IUS) may leads to higher vaginal bleeding over 6‐month compared with medroxyprogesterone (MPA) 10 mg (low certainty).