marginally significantP = 0.07
A marginally significant association (β = 0.06 h, 95% CI: −0.004, 0.12, P = 0.07) between TSH level in the second trimester and duration of the first stage of labor was observed, while TSH level in the third trimester was found to be significantly positively associated with duration of the first stage of labor (β = 0.12 h, 95% CI: 0.06, 0.18, P < 0.001).