Table 1.

Correlations among variables.

Variable	M	SD	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
1. HF HRV	32.78	16.2
2. LFHF ratio	3.19	3.07	− 0.76**
3. DFA alpha	1.19	0.24	− 0.89**	0.74**
4. mHRV Factor Score	0	0.98	0.98**	− 0.81**	− 0.96**
5. Maternal depression	5.6	4.4	− 0.24*	0.27*	0.16	− 0.24*
6. Maternal anxiety	33.24	10.5	− 0.2	0.22	0.1	− 0.19	0.75**
7. Maternal perceived stress	13.06	6.15	− 0.15	0.13	0.05	− 0.13	0.75**	0.77**
8. Maternal resting HR	77.22	11.3	− 0.41**	0.49**	0.50**	− 0.47**	− 0.01	− 0.04	− 0.01
9. State anxiety	30.76	9.4	− 0.1	0.14	0.01	− 0.08	0.68**	0.86**	0.74**	− 0.02
10. Income-to-needs	5.31	5.51	− 0.17	0.04	0	− 0.11	− 0.06	0.01	− 0.12	− 0.26*	− 0.04
11. Maternal age	32.86	5.45	0.07	− 0.08	− 0.08	0.11	− 0.01	− 0.03	0.01	− 0.27*	− 0.05	0.30**
12. Infant HRV Factor Score	0	0.99	0.27*	− 0.19	− 0.15	0.25*	− 0.14	− 0.17	− 0.15	0.05	− 0.14	− 0.21	− 0.01
13. Infant theta-beta ratio	5.62	1.45	− 0.30*	0.38**	0.22	− 0.30*	0	− 0.03	− 0.08	0.16	0	0.1	− 0.17	− 0.34**
14. Infant frontal alpha asymmetry	0.03	0.15	− 0.01	0.15	0.07	− 0.06	0.19	0.07	0.19	0.1	0.05	− 0.21	0.09	− 0.02	0.02
14. Dyadic physiological synchrony	0.04	0.29	− 0.04	0.03	0.07	− 0.05	0.13	0.26*	0.22	0.19	0.21	0	0.02	0.27*	− 0.14	0.04
15. Infant age (months)	3.47	0.39	− 0.04	0.17	− 0.04	− 0.04	0.04	0.06	0.09	0.17	0.12	− 0.16	0.11	− 0.03	0.18	0.12	− 0.06
16. Gestational age (weeks)	39.21	1.23	0.07	− 0.17	− 0.09	0.08	− 0.16	− 0.12	0.04	− 0.02	0	− 0.11	− 0.08	− 0.08	− 0.26*	− 0.02	0.05	− 0.27**

Pearson correlations of key variables. Significant correlations in the hypothesized direction between primary variables provided rationale for subsequent regression models.