Table 1 Demographics and clinical characteristics of the study cohort.

IQR, interquartile range; BMI, body mass index.

CharacteristicsTotal (n = 1293)Seropositive* (n = 80)Seronegative (n = 1213)P value
Age (in years), median (IQR)31 (27, 35)28 (24, 32)31 (27, 35)<0.001
Race/ethnicity, n (%)
  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/unknown§785 (6.4)73 (93.6)0.93
Pre-pregnancy BMI||, n (%)
  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
Diabetes, n (%)11310 (8.9)103 (91.1)0.22
Hypertension, n (%)40433 (8.2)371 (91.8)0.05
Asthma, n (%)19413 (6.7)181 (93.3)0.75
Cesarean delivery, n (%)40030 (7.5)370 (92.5)0.19
Preterm delivery at
gestational age <37 weeks,
n (%)
12811 (8.6)117 (91.4)0.23
Live-born infant, n (%)128279 (6.2)1203 (93.8)0.51

*Seropositivity was based on either IgG or IgM level of >0.48 arbitrary units.

†Difference 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 with proportion of non-Black women who were seropositive).

‡Row percentages are shown, which represent the percent of total in each characteristic (e.g., 9.7% of Black/Non-Hispanic women were seropositive).

§Race/ethnicity was unknown for two seropositive and 26 seronegative women; race was abstracted from documentation at the time of admission and in clinical practice and is usually self-reported.

||Pre-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.

¶Diagnoses were based on delivery admission ICD-10 diagnosis codes for diabetes (O24, E08-E13, and Z79.4), hypertension (O10, O11, O13-O16, I10-I13, and I15), and asthma (J45).