Associations between maternal lifetime stressors and negative events in pregnancy and breast milk-derived extracellular vesicle microRNAs in the programming of intergenerational stress mechanisms (PRISM) pregnancy cohort

Figures & data

Figure 1. A. Volcano plot of associations between EV-microRNA expression and LSCR scores. Estimates from robust linear regression adjusted for infant sex, maternal race, and maternal education. The 8 microRNAs meeting the a priori criteria for significance of p < 0.05 and |B_regression| > 0.2 are plotted in orange. B. Scatter plots of the 8 significant EV-microRNAs and LSCR scores with trend lines from linear models

Table 1. Participant characteristics (N = 74)

	N	%
Maternal
Age at delivery (years), median (IQR)	27.5	(23.1, 32.1)
Prepregnancy BMI, median (IQR)^a	25.0	(22.5, 30.9)
Prepregnancy obesity ^a.b	23	32.9%
Education^c
≤ High school diploma or GED	26	35.6%
> High school diploma or GED	47	64.4%
Prenatal tobacco smoke exposure
Environmental tobacco smoke exposure ^d	19	27.5%
Maternal smoking	11	14.9%
Race/ethnicity
White/other	6	8.2%
Black	41	56.2%
Hispanic	26	35.6%
Postpartum week of breast milk collection, median (IQR)	4.2	(2.6, 7.9)
Maternal lifetime stress
LSCR score, median (IQR)^e	7	(4, 9)
Negative life events during pregnancy
NLE score, median (IQR)^f	3	(1, 4)
Infant
Sex
Male (N, %)	41	55.4%
Female (N, %)	33	44.6%
Gestational age (weeks), median (IQR)	39.0	(38.9, 40.0)
Preterm (< 37 weeks gestation)	11	14.9%
Birth weight (g) (mean, SD)	3,050	(2,795, 3,425)
Low birth weight (< 2,500 g)	9	12.2%

a. N = 69. b. BMI ≥ 30. c. N = 73. d. N = 69; being exposed to environmental tobacco smoke for ≥ one hour/week during pregnancy. e. N = 73. f. N = 71.

Table 2. Summary of associations between EV-microRNAs in breast milk and maternal stress variables

			Associated with LSCR score		Associated with NLE score
Outcome	Number of microRNAs analysed	Criteria for significance	N	(%)	N	(%)
microRNA detection (yes/no)^a	173 detected in > 20% and < 80% of samples	p < 0.05	60	(35%)	44	(25%)
microRNA expression levels^b	205 detected in > 50% of samples	p < 0.05 and |Bregression| > 0.2	8	(4%)	17	(8%)

a. Logistic regression with the outcome of dichotomized detected/not detected for 173 microRNAs detected in > 20% of samples and < 80% of samples and adjusted for infant sex, maternal race, education, and postpartum week of breast milk collection. b. Robust linear regression with the outcome of continuous expression levels (-ΔC_q) and adjusted for infant sex, maternal race, education, and postpartum week of breast milk collection.

Figure 2. A. Volcano plot of associations between EV-microRNA expression and NLE scores. Estimates from robust linear regression adjusted for infant sex, maternal race, and maternal education. The microRNA meeting the a priori criteria for significance of p < 0.05 and |B_regression| > 0.2 is plotted in orange. B. Scatter plot of the significant EV-microRNA and NLE scores with trend line from linear models