Table 1.

SARS-Cov-2 seroprevalence among 5,991 patients at the end of pregnancy in the pre-vaccination era.

	Seronegative		Seropositive
Characteristic	n	row %	n	row %	P
All	5429	90.6	562	9.4
Age (years)					<0.001
< 25	899	84.8	161	15.2
25 - < 35	3143	90.9	316	9.1
≥ 35	1387	94.2	85	5.8
Pre-pregnancy body mass index (kg/m2)					<0.001
< 25	2542	93.4	180	6.6
25 - < 30	1344	89.8	152	10.2
≥ 30	1486	87.0	222	13.0
Missing	57	87.7	8	12.3
Parity					<0.001
0	2471	92.7	194	7.3
> 0	2958	88.9	368	11.1
Insurance					<0.001
Private	3235	95.1	166	4.9
Public	2194	84.7	396	15.3
Limited English proficiency					<0.001
Yes	170	73.3	62	26.7
No	5259	91.3	500	8.7
Race and ethnicity					<0.001
Hispanic	434	80.7	104	19.3
Non-Hispanic Asian	393	96.8	13	3.2
Non-Hispanic Black	2285	86.0	373	14.0
Non-Hispanic White	2076	97.3	57	2.7
None of the above, multiple, or unknown	241	94.1	15	5.9
Gestational age at delivery					0.09
Preterm (< 37 weeks)	477	88.5	62	11.5
Term (≥ 37 weeks)	4952	90.8	500	9.2