Exposure to prenatal stressors and infant autonomic nervous system regulation of stress

Figures & data

Figure 1. Flow chart for recruitment, enrollment and retention of study participants.

Table 1. Characteristics of women and infants.

Characteristic	M (SD) or N (%)
Women
Age*	33.56 (5.7)
Race/Ethnicity**
African American/Black	51 (21.8)
Asian American	38 (16.3)
European American/White***	83 (35.6)
Hawaiian/Pacific Islander	4 (1.9)
Hispanic American/Latina	56 (24.0)
Native American	1 (0.4)
Education**
High School/GED	87 (37.3)
Associate Degree	14 (6.0)
Bachelors’ Degree	46 (19.7)
Graduate Degree	86 (37.0)
Depression*	5.53 (4.69)
Obstetric Complications*	3.37 (1.95)
Infants
Sex (Female)**	116 (49.8)
Gestational Age*	36.93 (2.87)
Neonatal Morbidity*	137.45 (249)

* M = mean, SD = standard deviation;.

** N = number.

*** Not Hispanic.

Table 2. Percent of women who reported stressful events in various stressor domains.

Domains	N	%
Housing Problems	104	44.8
Work Challenges	37	16.6
Financial Strains	27	11.6
Unsafe Community	21	9.0
Medical Illnesses	19	8.4
Relationship Problems	19	8.2
Authority Problems	14	6.2
Legal Problems	13	5.7
Domestic Violence	12	5.3
Prejudice	11	4.8

N = number.

Table 3. Mean (SE) infant HRV for low frequency (LF), high frequency (HF), and the LF/HF ratio for resting state, reactivity to the stressor, and the post-stressor period at 1, 6, and, 12 months postnatal.

	1 Month	6 Month	12 Months
Baseline, resting state
LF ms^2	4.71 (.10)	5.33 (.12)	5.68 (.13)
HF ms^2	3.68 (.13)	4.11 (.15)	4.64 (.16)
LF/HF ratio	1.05 (.10)	1.25 (.12)	1.03 (.13)
Post-stressor period
LF ms^2	4.77 (.12)	5.21 (.13)	5.45 (.14)
HF ms^2	3.55 (.14)	4.13 (.16)	4.59 (.17)
LF/HF ratio	1.22 (.10)	1.08 (.11)	0.86 (.12)
Reactivity to the stressor
LF ms^2	0.06 (.12)	0.14 (.13)	0.21 (.15)
HF ms^2	0.08 (.13)	0.01 (.15)	0.03 (.16)
LF/HF ratio	0.08 (.13)	0.17 (.14)	0.20 (.15)

ms²=milliseconds squared; all values are log transformed; SE = standard error.

Table 4. Multilevel regression for the association of prenatal stressors with low frequency (LF), high frequency (HF) and LF/HF ratio HRV during a baseline, resting state across the first year of life*.

	Coefficient	SE	p-value	98.33% CI
LF
Neonatal Morbidity	−.001	.00	.05	−.0011, .0001
Women’s Depression	−.018	.02	.34	−.0660, .0287
Prenatal Stressors	−.009	.01	.12	−.0235, .0049
HF
Neonatal Morbidity	−.001	.00	.07	−.0014, .0002
Women’s Depression	−.004	.02	.87	−.0626, .0549
Prenatal Stressors	−.001	.01	.94	−.0180, .0170
LF/HF Ratio
Neonatal Morbidity	−.001	.00	.74	−.0005, .0007
Women’s Depression	−.012	.02	.37	−.0648, .0294
Prenatal Stressors	−.009	.00	.13	−.0228, .0051

* Adjusting for Neonatal Morbidity and Women’s Depression; HRV = Heart Rate Variability; SE = Standard Error; CI = Confidence Interval.

Table 5. Multilevel regression for the association of prenatal stressors with low frequency (LF), high frequency (HF) and the LF/HF ratio HRV during a post-stressor period across the first year of life*.

	Coefficient	SE	p-value	98.33% CI
LF
Neonatal Morbidity	−.001	.00	.02	−.0014, .0004
Women’s Depression	−.006	.02	.79	−.0467, .0583
Prenatal Stressors	−.023	.01	.001	−.0383, −.0075
HF
Neonatal Morbidity	−.001	.00	.03	−.0018, .0001
Women’s Depression	−.003	.02	.91	−.0686, .0625
Prenatal Stressors	−.011	.01	.15	−.0303, .0076
LF/HF Ratio
Neonatal Morbidity	−.005	.00	.56	−.0004, .0008
Women’s Depression	−.006	.02	.72	−.0380, .0515
Prenatal Stressors	−.011	.01	.04	−.0244, .0019

* Adjusting for Neonatal Morbidity and Women’s Depression; HRV = Heart Rate Variability; SE = Standard Error; CI = Confidence Interval.

Table 6. Multilevel regression for the association of prenatal stressors with HRV reactivity to a stressor for low frequency (LF), high frequency (HF) and the LF/HF ratio across the first year of life*.

	Coefficient	SE	p-value	98.33% CI
LF
Neonatal Morbidity	−.000	.00	.24	−.0011, .0004
Women’s Depression	.020	.02	.36	−.0332, .0004
Prenatal Stressors	−.012	.00	.06	−.0280, .0036
HF
Neonatal Morbidity	−.000	.00	.12	−.0290, .0061
Women’s Depression	.006	.02	.14	−.0013, .0003
Prenatal Stressors	−.011	.00	.52	−.4142, .2406
LF/HF Ratio
Neonatal Morbidity	.000	.00	.70	−.0165, .0149
Women’s Depression	.015	.00	.48	−.0006, .0008
Prenatal Stressors	−.001	.03	.90	−.2279, .3970

* Adjusting for Neonatal Morbidity and Women’s Depression; HRV = Heart Rate Variability; SE = Standard Error; CI = Confidence Interval.

Table 7. Linear regression for the association of prenatal stressors with low frequency heart rate variability at 1 month, 6 months and 12 months postnatal*.

	Beta	SE	p-value	98.33% CI
1 Month Postnatal
Neonatal Morbidity	−.28	.00	.003	−.001, .000
Women’s Depression	−.07	.01	.437	−.038, .017
Prenatal Stressors	.03	.01	.754	−.022, .030
6 Months Postnatal
Neonatal Morbidity	−.03	.00	.778	.000, .000
Women’s Depression	.08	.01	.448	−.015, .033
Prenatal Stressors	−.44	.01	.001	−.054, −.017
12 Months Postnatal
Neonatal Morbidity	.09	.00	.426	−.000, .001
Women’s Depression	−.02	.01	.896	−.033, .029
Prenatal Stressors	−.37	.01	.005	−.070, −.013

* Adjusting for Neonatal Morbidity and Women’s Depression; SE = Standard Error; CI = Confidence Interval.