Summary of findings 4. Stillbirth.

Patient or population: women with threatened miscarriage or a history of recurrent miscarriage Interventions: multiple progestogens (vaginal micronized progesterone, oral micronized progesterone, dydrogesterone and 17‐α‐hydroxyprogesterone) Comparison: placebo and dydrogesterone Outcome: stillbirth Settings: hospitals
Treatment	Direct evidence		Indirect evidence		Anticipated absolute effects for direct estimate
	RR (95% CI)	Certainty	RR (95% CI)	Certainty	Risk with intervention	Risk with comparator	Risk difference with intervention
Threatened miscarriage
Vaginal micronized progesterone versus placebo	0.83 [0.25, 2.71]	⊕⊕⊝⊝ LOWa	Unavailable	‐	2 per 1000 (vaginal micronized progesterone)	3 per 1000 (placebo)	1 fewer per 1000 (from 2 fewer to 5 more)
Dydrogesterone versus placebo	0.33 [0.01, 8.13]	⊕⊝⊝⊝ VERY LOWb	Unavailable	‐	2 per 1000 (dydrogesterone)	5 per 1000 (placebo)	3 fewer per 1000 (from 5 fewer to 35 more)
17‐α‐hydroxyprogesterone versus placebo	Unavailable	‐	Unavailable	‐	See comment*	See comment**	See comment***
Oral micronized progesteroneversus dydrogesterone	Unavailable	‐	Unavailable	‐	See comment*	See comment**	See comment***
Vaginal micronized progesterone versus dydrogesterone	Unavailable	‐	2.52 [0.07, 88.08]	⊕⊝⊝⊝ VERY LOWc	See comment*	See comment**	See comment***
Recurrent miscarriage
Vaginal micronized progesteroneversus placebo	0.54 [0.05, 5.91]	⊕⊕⊝⊝ LOWa	Unavailable	‐	3 per 1000 (vaginal micronized progesterone)	5 per 1000 (placebo)	2 fewer per 1000 (from 4 fewer to 23 more)
Dydrogesterone versus placebo	Unavailable	‐	Unavailable	‐	See comment*	See comment**	See comment***
17‐α‐hydroxyprogesteroneversus placebo	Unavailable	‐	Unavailable	‐	See comment*	See comment**	See comment***
Oral micronized progesteroneversus dydrogesterone	Unavailable	‐	Unavailable	‐	See comment*	See comment**	See comment***
*No included studies or there are no events in included studies to estimate the baseline risk. **Absolute risk with intervention cannot be estimated in the absence of absolute risk with the comparator. ***Risk difference cannot be estimated in the absence of absolute risks with intervention and the comparator. CI: Confidence interval; RR: Risk ratio.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

^a Direct evidence downgraded ‐2 due to severe imprecision (wide 95% CIs and number of events less than 30).

^b Direct evidence downgraded ‐1 due to serious limitations in study design and ‐2 for severe imprecision (wide 95% CIs and number of events less than 30).

^c Indirect evidence downgraded ‐1 due to serious limitations in study design and ‐2 for severe imprecision (wide 95% CIs and number of events less than 30).