The LARC review reports both sides of a trade and grades them separately, which is more useful than it first appears.
The benefit — fewer pregnancies at six months — is moderate certainty, with a risk ratio of 0.16 whose interval runs from 0.04 to 0.71. The harm — expulsion after vaginal delivery — is high certainty, with a risk ratio of 5.09. So the better-established finding is the harm, while the benefit rests on fewer events and weaker evidence.
That asymmetry does not settle the decision, and it should not be read as a reason to prefer delayed insertion. What it does is tell you where the uncertainty sits, which is what a counselling conversation actually needs: you can tell a woman confidently that immediate insertion carries a real expulsion risk, and rather less confidently how much pregnancy risk it removes.
The habit: when a review grades outcomes separately, note where the certainty differs before weighing them. Two numbers presented side by side invite equal weight, and they rarely deserve it.
- Check whether benefit and harm carry the same certainty rating
- Wide intervals with few events mean an imprecise benefit estimate
- Higher certainty on harm does not mean harm outweighs benefit
- Say which side you are confident about when counselling
- GRADE ratings exist precisely so this asymmetry is visible
The statistics, in plain English
GRADE certainty ratings reflect risk of bias, imprecision, inconsistency, indirectness and publication bias — not effect size. A large effect with high certainty and a large effect with low certainty look identical in a forest plot and mean very different things. This is why a well-conducted review reports the rating alongside every estimate.
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