Table 2

Preterm birth among twin and singleton pregnancies

Twin pregnancies (N=1859)Singleton pregnancies (N=117 593)Relative riskAdjusted relative risk*
Preterm birth (<37 weeks)873 (47.6%)19 462 (16.7%)2.8, 95% CI 2.7 to 3.02.8, 95% CI 2.7 to 2.9
Missing (%)25 (1.3)1391 (1.2)
Very preterm birth (<32 weeks)217 (11.8%)4664 (4.0%)2.9, 95% CI 2.6 to 3.43.0, 95% CI 2.6 to 3.4
Missing (%)25 (1.3)1391 (1.2)
  • *Adjusted for maternal age, gravida and educational attainment and maternal HIV status.