Elevated resting tonea N= 567 Normal resting tone N= 1643
p-value
Maternal demographics
     Age (y) 24.3 ± 5.34 26.0 ± 5.9 <0.01
     Advanced maternal ageb 29 (5.1) 157 (9.6) <0.01
Race Black White Latina Other 422 (75.1) 94 (16.7) 30 (5.3) 16 (2.9) 1164 (71.2) 321 (16.7) 101 (6.2) 48 (2.9)
0.35
     Body mass index (kg/m2) 33 (29, 39) 32 (28, 38) <0.01
     Maternal weight (kg) 89.0 (74.5-106.1) 85.3 (73.5-101.6) 0.02
Pregnancy characteristics
     Gestational age (Weeks) 39.3 ± 1.2 39.1 ± 1.3 0.04
     Gestational age <39 weeks 218 (38.5) 706 (43.0) 0.06
     Nulliparity 87 (50.6) 622 (37.9) <0.01
      Prior cesarean delivery 51 (9.0) 166 (10.1) 0.44
Maternal comorbidities
     Chronic hypertension 37 (6.5) 109 (6.6) 0.93
     Hypertensive disorder of pregnancy 125 (22.1) 334 (20.3) 0.39
     Pregestational diabetes 13 (2.3) 20 (1.2) 0.07
Fetal Characteristics
     Fetal growth restriction 90 (15.9) 272 (16.6) 0.71
     Birthweight (g) 3165 ± 472 3164 ± 471 0.17
     Male sex 286 (50.4 ) 817 (49.7) 0.77
aElevated tone defined as > 75th percentile bDefined as maternal age ≥ 35 at time of delivery *Data presented as N(%), Mean ± SD, or Median (IQR) aElevated tone defined as > 75th percentile bDefined as maternal age ≥ 35 at time of delivery *Data presented as N(%), Mean ± SD, or Median (IQR) aElevated tone defined as > 75th percentile bDefined as maternal age ≥ 35 at time of delivery *Data presented as N(%), Mean ± SD, or Median (IQR) aElevated tone defined as > 75th percentile bDefined as maternal age ≥ 35 at time of delivery *Data presented as N(%), Mean ± SD, or Median (IQR)