Table 4

Interpregnancy interval, maternal age, other demographic factors, and risk of adverse obstetric outcome

Odds ratios (95% CI) for interpregnancy interval <6 monthsOdds ratios (95% CI) for age <20 years
OutcomeCrudeAdjusted 1Adjusted 2Adjusted 3CrudeAdjusted 1Adjusted 2Adjusted 3
Delivery 24-32 weeks3.1 (1.9 to 4.9)2.3 (1.4 to 3.8)2.5 (1.5 to 4.0)2.2 (1.4 to 3.6)4.0 (2.6 to 6.2)3.2 (2.0 to 5.1)2.6 (1.6 to 4.2)2.0 (1.2 to 3.4)
Delivery 33-36 weeks2.0 (1.6 to 2.4)1.7 (1.3 to 2.1)1.7 (1.4 to 2.1)1.6 (1.3 to 2.0)2.3 (1.9 to 2.9)2.2 (1.7 to 2.7)1.6 (1.3 to 2.1)1.5 (1.2 to 2.0)
Neonatal death unrelated to congenital abnormality or rhesus5.4 (1.9 to 15.2)3.8 (1.3 to 11.0)4.3 (1.5 to 12.3)3.6 (1.2 to 10.7)8.4 (3.2 to 22.2)5.6 (2.0 to 15.9)5.0 (1.6 to 15.7)3.5 (1.0 to 11.6)
  • Adjusted 1=adjusted only for maternal age or interpregnancy interval; adjusted 2=adjusted only for maternal smoking, socioeconomic deprivation, height, previous birth weight vigesimal, and previous caesarean section; adjusted 3=adjusted for maternal smoking, socioeconomic deprivation, height, previous caesarean section, birth weight vigesimal, and maternal age or interpregnancy interval.