Table 1:

Participant Characteristics

Descriptive Variable		Overall
		N	%
Income	High Middle Low Not Available	16 9 12 2	41 23.1 30.8 5.1
Maternal Psychiatric History	Yes No	13 26	33.3 66.7
Paternal Psychiatric History	Yes No	5 34	12.8 87.2
Cesarean Section	Yes No	20 19	51.3 48.7
Single or Twin Gestation	Twin Singleton	24 15	61.5 38.5
Sex	Male Female	16 23	41 59
NICU	Yes No	10 29	25.6 74.4
Maternal Ethnicity	White Black Asian Native American	32 6 0 1	82.1 15.4 0 2.6
Paternal Ethnicity	White Black Asian Native American	28 9 2 0	71.8 23.1 5.1 0

Descriptive Variable		Overall
		N	%
Older Siblings	Yes No	17 22	43.6 56.4
Currently Breastfed	Yes No	14 25	35.9 64.1
Ever Given Formula	Yes No	26 13	66.7 33.3
Currently Given Formula	Yes No	10 29	25.6 74.4
Given Milk Other Than Breastmilk or Formula	Yes No	34 5	87.2 12.8
Type of Other Milk	Breastmilk Exclusively Cow’s Milk Other (almond, soy)	5 31 3	12.8 79.5 7.7
Symptoms of Illness in Previous Week	Yes No	21 18	53.8 46.2
Gastrointestinal Symptoms in Previous Week	Yes No	5 34	12.8 87.2
Antibiotics within Last Year	Yes No	0 39	0 100
Antibiotics During Pregnancy	Yes No	5 34	12.8 87.2

Descriptive Variable	Overall
	N	Mean ± SD
Gestational Age at Birth (days)	39	259.5 ± 19.5
Birth Weight (grams)	39	2810 ± 716.8
APGAR at 5 Minutes	39	8.5 ± 1.1
Maternal Age at Birth (years)	39	30.8 ± 4.7
Maternal Education (years)	39	16.9 ± 2.6
Paternal Age at Birth (years)	39	33 ± 5.5
Paternal Education (years)	39	16 ± 3.5
Age at MRI (days)	39	404.1 ± 38.3