The major risk with big babies is possible shoulder dystocia where shoulders can get stuck coming out. When we were considering, I found this resource quite helpful (http://evidencebasedbirth.com/evidence-for-induction-or-c-section-for-big-baby/).
My gynae also told us that c-sec is better for baby (no risk of injuries or trauma) but worse for mum (longer healing time) so we opted for a c-section.
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