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Table 2 Association between pregnancy duration and maternal salivary cortisol (nmol/L) measured at ≤20 wk., 28 wk., and 36 wk. gestation a

From: Increased risk of preterm delivery with high cortisol during pregnancy is modified by fetal sex: a cohort study

Duration of gestation (wk)

  
 

n (%)

Unadjusted β coefficient

(95% CI)

P

Adjusted β coefficient

(95% CI), Model 1b

p

Adjusted β coefficient

(95% CI), Model 2c

p

All women

  ≤ 20 wk. log cortisol

783 (100%)

−0.43 (− 0.66, − 0.20)

<.001

− 0.42 (− 0.66, − 0.17)

0.001

− 0.39 (− 0.64, − 0.14)

0.002

 28 wk. log cortisol

741 (94.6%)

−0.43 (− 0.67, − 0.19)

<.001

−0.44 (− 0.73, − 0.15)

0.003

−0.49 (− 0.78, − 0.20)

0.001

 36 wk. log cortisol

658 (84.0%)

−0.25 (− 0.49, 0.00)

0.050

−0.29 (− 0.54, − 0.02)

0.032

−0.23 (− 0.49, 0.03)

0.084

 Change log cortisold

654 (83.5%)

0.09 (−0.08, 0.27)

0.297

0.08 (−0.11, 0.27)

0.409

0.07 (−0.12, 0.27)

0.447

Female fetal sex

  ≤ 20 wk. log cortisol

411 (100%)

−0.19 (− 0.51, 0.12)

0.233

− 0.25 (− 0.59, 0.09)

0.151

−0.24 (− 0.59, 0.10)

0.160

 28 wk. log cortisol

389 (94.6%)

− 0.37 (− 0.71, − 0.03)

0.031

−0.37 (− 0.77, 0.04)

0.079

−0.37 (− 0.78, 0.04)

0.077

 36 wk. log cortisol

338 (82.2%)

0.20 (− 0.11, 0.51)

0.212

0.12 (− 0.21, 0.45)

0.468

0.11 (− 0.22, 0.43)

0.525

 Change log cortisold

338 (82.2%)

0.21 (−0.02, 0.44)

0.073

0.19 (−0.05, 0.43)

0.123

0.19 (−0.06, 0.43)

0.129

Male fetal sex

  ≤ 20 wk. log cortisol

372 (100%)

−0.68 (− 1.02, − 0.34)

<.001

−0.61 (− 0.97, − 0.25)

0.001

−0.57 (− 0.93, − 0.20)

0.003

 28 wk. log cortisol

348 (93.5%)

−0.50 (− 0.84, − 0.16)

0.004

−0.44 (− 0.85, − 0.03)

0.037

−0.52 (− 0.93, − 0.10)

0.016

 36 wk. log cortisol

316 (84.9%)

−0.82 (− 1.20, − 0.43)

<.001

−0.85 (− 1.26, − 0.44)

<.001

−0.74 (− 1.15, − 0.32)

0.001

 Change log cortisold

316 84.9%)

− 0.04 (− 0.32, 0.24)

0.775

−0.04 (− 0.35, 0.27)

0.795

−0.05 (− 0.37, 0.26)

0.752

  1. aAssociations are presented for log-transformed cortisol concentrations. The decrease in pregnancy duration can be calculated for an x percent increase in cortisol concentration by multiplying the coefficient by log(1.x). E.g., for a 50% increase in cortisol at ≤20 wk. using Model 1, there is a decrease in pregnancy duration by − 0.42*log(1.50) = − 0.17 wk., or − 1.2 days
  2. bModel 1 adjusted for supplementation group, gestational age at enrollment, parity, maternal age, education, food insecurity, asset index, BMI, fetal sex, twin pregnancy, time between waking and saliva collection, and time between last food or drink (except water) and saliva collection
  3. cModel 2 adjusted for all variables in Model 1, plus AGP and CRP
  4. dChange between ≤20 wk. and 36 wk. cortisol concentrations