Table 6. Summary of findings table.
| [Preconception care] compared to [no preconception care] or [routine care] for [improving maternal and perinatal outcomes] | ||||||
|---|---|---|---|---|---|---|
|
Patient or population: [improving maternal and perinatal outcomes] Setting: Hospital setting Intervention: [Preconception care] Comparison: [no preconception care] or [routine care] | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with [no preconception care] or [routine care] | Risk with [Preconception care] | |||||
| Congenital malformations follow up: mean 9 months a | 70 per 1,000 | 20 per 1,000 (15 to 28) | RR 0.29 (0.21 to 0.40) | 5903 (25 observational studies) | ⨁⨁⨁⨁ HIGH | [Preconception care] results in large reduction in congenital malformations. |
| Perinatal mortality follow up: mean 9 months b | 46 per 1,000 | 21 per 1,000 (13 to 33) | RR 0.46 (0.30 to 0.73) | 3071 (10 observational studies) | ⨁⨁⨁◯ MODERATE | [Preconception care] results in large reduction in perinatal mortality. |
| Gestational age at booking follow up: mean 9 months c | The mean gestational age at booking was 8.5 Weeks | mean 1.31 Weeks fewer (1.4 fewer to 1.23 fewer) | - | 1081 (5 observational studies) | ⨁◯◯◯ VERY LOW | [Preconception care] may result in a slight reduction in gestational age at booking. |
| Hemoglobin A1c (HbA1c) follow up: mean 9 months d | The mean hemoglobin A1c was 8.3% | mean 1.32% lower (1.34 lower to 1.23 lower) | - | 4927 (24 observational studies) | ⨁⨁⨁◯ MODERATE | [Preconception care] likely results in a reduction in HbA1c. |
| Maternal hypoglycemia follow up: mean 9 months e | 241 per 1,000 | 333 per 1,000 (258 to 432) | RR 1.38 (1.07 to 1.79) | 686 (3 observational studies) | ⨁◯◯◯ VERY LOW | [Preconception care] has no effect on Maternal hypoglycemia |
| Preterm delivery follow up: mean 9 months f | 250 per 1,000 | 213 per 1,000 (183 to 248) | RR 0.85 (0.73 to 0.99) | 2414 (9 observational studies) | ⨁⨁⨁◯ MODERATE | [Preconception care] likely results in a slight reduction in preterm delivery. |
| Small for gestational age follow up: mean 9 months g | 88 per 1,000 | 46 per 1,000 (32 to 66) | RR 0.52 (0.37 to 0.75) | 2261 (6 observational studies) | ⨁⨁⨁◯ MODERATE | [Preconception care] reduces small for gestational age. |
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
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 Upgraded to high because of large effect size, consistency of direction of effect, no indirectness of evidence, and no heterogeneity or publication bias.
b Upgraded to moderate due to the narrow confidence intervals, consistency of direction of effect, no indirectness of evidence, and low risk of bias, no heterogeneity or publication bias.
c Downgraded to very low-grade due to the high risk of bias in the study with the largest weight [39] and high unexplained heterogeneity
d Upgraded to moderate-certainty level because of low bias (77% of the participants were from studies at low risk of bias), while heterogeneity can be explained by long span of time between the first and the last study (1982 and 2017), The publication bias can be explained with the heterogeneity.
e Downgraded to very low-level certainty because, inconsistency, low bias and high heterogeneity
f Upgraded to moderate-certainty level because of narrow confidence intervals, consistency of direction of effect, no indirectness of evidence, low risk of bias, low heterogeneity, no evidence of selective reporting.
g Upgraded to moderate-certainty level because the large effect size with precise narrow confidence interval, consistency of direction of effect, no indirectness of evidence, and no heterogeneity and no evidence of selective reporting.