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Table 3 Assessment of the quality of evidence based on GRADE approach

From: COVID-19 vaccination during pregnancy: a systematic review and meta-analysis

Patient or population: Outcomes of pregnant women received COVID-19 vaccine compared with unvaccinated group

Outcomes

No of participants

(studies)

Certainty of the evidence

(GRADE)

Adverse neonatal outcome

289,414

(10 observational studies)

Moderate

Small for gestational age

196,739

(8 observational studies)

Moderate

5-min Apgar < 7

269,806

(7 observational studies)

Very lowa,b

Cesarean delivery

112,618

(7 observational studies)

Moderate

Post-partum hemorrhage

112,618

(7 observational studies)

Moderate

Preterm birth

34,782

(7 observational studies)

Low b

Stillbirth

9927

(4 observational studies)

Lowc

  1. 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
  2. a Imprecision
  3. b Inconsistency between the pooled result and the result of most of the included studies
  4. c Small sample size