TABLE 4

Factors Associated With Singleton Late-Preterm Deliveries With No Recorded Indication

VariableFrequency, %Univariate Odds Ratio (95% CI)aAdjusted Odds Ratio (95% CI)b
IndicatedNo Recorded Indication
Maternal age, y
    <2014.6010.730.56 (0.53–0.59)0.65 (0.61–0.69)
    20–2427.0024.300.69 (0.65–0.72)0.71 (0.67–0.74)
    25–2924.3125.100.79 (0.75–0.83)0.78 (0.74–0.82)
    30–3420.6622.990.85 (0.81–0.89)0.84 (0.80–0.88)
    35–3910.7113.300.95 (0.90–1.00)0.93 (0.88–1.0)
    ≥402.733.571.00
Maternal race/ethnicity
    Non-Hispanic white51.4054.421.00
    Non-Hispanic black20.5318.880.87 (0.85–0.89)0.91 (0.88–0.93)
    Hispanic21.6621.410.93 (0.91–0.95)1.01 (0.99–1.04)
    Other5.864.830.78 (0.75–0.81)0.81 (0.77–0.84)
Maternal education, y
    <1226.1022.830.81 (0.79–0.83)0.94 (0.92–0.97)
    1232.8533.240.94 (0.92–0.96)1.01 (0.99–1.03)
    ≥1339.5442.701.00
Region of occurrence
    Northeast15.9713.051.00
    Midwest21.7020.981.18 (1.15–1.22)1.20 (1.16–1.23)
    South40.2044.741.36 (1.33–1.40)1.40 (1.36–1.44)
    West22.1321.231.17 (1.14–1.21)1.18 (1.14–1.22)
Parity
    Primipara41.0635.100.78 (0.76–0.79)0.80 (0.78–0.82)
    Multipara58.6164.521.00
Previous ≥4000-g infant
    Reported0.610.801.33 (1.20–1.47)1.18 (1.06–1.31)
    Not reported98.6397.721.00
Previous preterm or SGA infant
    Reported3.282.390.73 (0.69–0.77)0.66 (0.63–0.70)
    Not reported95.9696.141.00
  • SGA indicates small for gestational age.

  • a Data show the odds ratio for delivery with no recorded indication(95% confidence interval).

  • b Data show the odds ratio adjusted for all of the variables in the table.