Table 1 Demographics and clinical characteristics of the study cohort.

CharacteristicsTotal
(n = 1,293)
Seropositive1
(n = 80)
Seronegative
(n = 1,213)
p-value2
Age (in years), median (IQR)31 (27, 35)28 (24, 32)31 (27, 35)<0.001
Race/ethnicity, n (%)3
Black/Non-Hispanic53752 (9.7)485 (90.3)<0.001
White/Non-Hispanic4479 (2.0)438 (98.0)<0.001
Hispanic/Latino12513 (10.4)112 (89.6)0.04
Asian1061 (0.9)105 (99.1)0.01
Other/Unknown4785 (6.4)73 (93.6)0.93
Pre-pregnancy BMI5, n (%)3
Overweight (25.0 to <30.0)34528 (8.1)317 (91.9)0.07
Obese (≥30.0)33727 (8.0)310 (92.0)0.09
Diabetes6, n (%)311310 (8.9)103 (91.1)0.22
Hypertension6, n (%)340433 (8.2)371 (91.8)0.05
Asthma6, n (%)319413 (6.7)181 (93.3)0.75
Cesarean delivery, n (%)340030 (7.5)370 (92.5)0.19
Preterm delivery at gestational age <37 weeks, n (%)312811 (8.6)117 (91.4)0.23
Live-born infant, n (%)31,28279 (6.2)1,203 (93.8)0.51

1Seropositivity was based on either IgG or IgM level >0.48 arbitrary units. 2Difference in maternal age was tested using Mann-Whitney U test, differences in proportion of all other characteristics were tested using χ2 tests or Fisher’s exact test as appropriate. For race/ethnicity and pre-pregnancy BMI, difference was tested at each level of the characteristic (e.g., proportion of Black women who were seropositive compared to proportion of non-Black women who were seropositive). 3Row percentages are shown which represent the percent of total in each characteristic (e.g., 9.7% of Black/Non-Hispanic women were seropositive). 4Race/ethnicity was unknown for 2 seropositive and 26 seronegative women; race was abstracted from documentation at time of admission and in clinical practice, is usually self-reported. 5Pre-pregnancy BMI was missing for 2 seropositive and 12 seronegative women; pre-pregnancy BMI was abstracted from documentation in the medical record, or from patient’s self-reported entry in birth registration. 6Diagnoses were based on delivery admission International Classification of Diseases, 10th revision diagnosis codes for diabetes (O24, E08-E13, Z79.4), hypertension (O10, O11, O13-O16, I10-I13, I15), and asthma (J45). BMI, body mass index; IQR, interquartile range.