Table 2:

Event rates for serious motor vehicle crashes during the baseline period and the second trimester of pregnancy, by maternal characteristic

CharacteristicTotal no. of eventsEvent rate*Relative risk (95% CI)
BaselinePregnancy
Full cohort76794.556.471.42 (1.32–1.53)
Age, yr
< 3044565.837.551.30 (1.17–1.44)
≥ 3032233.475.551.60 (1.43–1.79)
Socioeconomic status
Higher26764.406.111.39 (1.22–1.58)
Middle16764.817.671.59 (1.37–1.86)
Lower33274.596.261.36 (1.22–1.53)
Home location
Urban64774.216.311.50 (1.38–1.62)
Rural12027.787.991.03 (0.83–1.28)
Pregnancy duration
Preterm5625.365.050.94 (0.69–1.32)
At-term62254.526.601.46 (1.35–1.59)
Post-term8924.346.331.46 (1.18–1.82)
Delivery mode
Vaginal53704.556.521.44 (1.31–1.57)
Cesarean23094.566.331.39 (1.21–1.60)
Perinatal complication
Present37644.486.391.43 (1.28–1.59)
Absent39154.626.541.42 (1.28–1.58)
Duration of hospital stay, d
≤ 244634.306.471.50 (1.37–1.66)
≥ 332164.956.471.31 (1.16–1.48)
Infant sex
Girl35644.566.971.53 (1.38–1.70)
Boy36964.546.131.35 (1.21–1.51)
Maternal experience
Primiparous48064.546.021.33 (1.20–1.46)
Multiparous28734.567.221.58 (1.41–1.78)
  • Note: CI = confidence interval.

  • * Event rates were calculated per 1000 individuals annually during corresponding interval. Baseline spans the 3-year period before conception; pregnancy spans 3 total months of the second trimester. One month was defined as 28 consecutive days.

  • Event rate for entire population of all ages is about 2 crashes per 1000 drivers annually.