Table 2 Full linear mixed model for melatonin levels across the day (n = 70)

Intercept

1.819

0.156

11.656

< 0.001**

6.17pmol/l

Trimester = 2

-0.007

0.107

-0.062

0.951

0.7% lower melatonin in T = 3

Morning (9:00–15:00 h)

Collection time (linear)

-0.429

0.079

-5.383

< 0.001**

8.9% decrease per hour

Collection time × Trimester

-0.013

0.108

-0.122

0.903

1.3% steeper in T = 3

Evening (15:00–03:00 h)

Collection time (linear)

0.442

0.035

12.687

< 0.001**

9.3% increase per hour

Collection time (quadratic)

0.163

0.002

2.900

0.004**

3.0% steeper per hour

Collection time × Trimester

0.002

0.011

0.082

0.935

0.2% steeper in T = 3

Random effects

Variance component

S.E.

Wald z

p -value

Residual

0.23

0.02

11.94

< 0.001**

Intercept (person-level)

0.46

0.27

1.68

0.093

Covariance (person-level)

-0.38

0.24

-1.60

0.109

Time (person-level)

0.36

0.22

1.61

0.107