Table 3.

Correlation matrix of sleep, psychosocial measures, and preterm birth across pregnancy

	14-16 Weeks				24-26 Weeks				30-32 Weeks
	PSQI	PSS	CES-D#	STAI	PSQI	PSS	CES-D	STAI	PSQI	PSS	CES-D	STAI
PSS	0.32**	–	–	–	0.43**	–	–	–	0.49**	–	–	–
CESD	−0.20*	−0.09	–	–	0.07	0.04	–	–	0.13	0.02	–	–
STAI	0.40**	0.72**	−0.09	–	0.45**	0.73**	−0.01	–	0.53**	0.75**	0.06	–
Preterm Birth^	−0.28**	−0.08	−0.11	−0.13	−0.07	−0.09	−0.02	−0.17*	−0.24**	−0.23**	−0.12	−0.31**

PSQI, Pittsburgh Sleep Quality Index; STAI, State-Trait Anxiety Inventory; PSS, Perceived Stress Scale; CES-D, Center for Epidemiologic Studies- Depression Scale. Value is minus the sleep item.

^*P < 0.01,

^**P < 0.001.

^{^}point biserial correlations.