Sphincter rupture Sphincter rupture All vaginal births Crude Crude Adjusted (maternal characteristics) Adjusted (maternal characteristics) Adjusted (delivery mode) Adjusted (delivery mode)
Birth weight (g) n (%) N OR (95%CI) OR (95%CI) OR (95%CI)
<2500 231 (0.9) 25 472 0.24 0.21–0.27 0.17 0.15–0.20 0.19 0.17–0.22
2500–2999 1845 (1.8) 101 202 0.48 0.45–0.50 0.36 0.34–0.38 0.38 0.36–0.40
3000–3499 8641 (2.7) 323 256 0.70 0.68–0.72 0.59 0.57–0.60 0.61 0.60–0.63
3500–3999 13 713 (3.8) 357 012 1.00 ref 1.00 Ref 1.00 Ref
4000–4499 7829 (5.2) 149 762 1.36 1.33–1.40 1.65 1.60–1.69 1.56 1.52–1.60
≥4500 2324 (7.2) 32 284 1.87 1.80–1.96 2.84 2.73–2.96 2.61 2.50–2.72