Table 1. Participant demographics.

MA, maternal age; GA, gestational age; MAD, median absolute deviation; na, not available.

Cohort 1 (n = 72,932)Cohort 2 (n = 16,885)Cohort 1 versus cohort 2
VariableNo flagFlaggedPNo flagFlaggedPP (no flag)P (flagged)
Samples, n (% total)72,414 (99.29%)518 (0.71%)na16,776 (99.35%)109 (0.65%)na0.383 (difference in
proportions of flagged
versus nonflagged,
comparing cohort 1 to
cohort 2)
MA (years)
  Median ± MAD35.6 ± 4.436.1 ± 5.10.00334.4 ± 4.435.7 ± 5.50.01<0.00050.945
  Mean ± SD34.6 ± 5.435.1 ± 5.834.4 ± 4.335.6 ± 4.9
  Min–Max13.8–66.614.0–50.718.2–62.219.8–46.4
GA (weeks)
  Median ± MAD12.0 ± 3.012.0 ± 3.00.8310.0 ± 010.0 ± 00.847<0.0005<0.0005
  Mean ± SD13.8 ± 4.213.9 ± 4.411.0 ± 1.911.2 ± 2.6
  Min–Max10–4010–3510–3610–31
Trimester (% of samples)
  First (10–13.9 weeks)47,498 (65.60%)331 (63.80%)0.40215,560 (92.80%)97 (89.00%)0.025<0.0005<0.0005
  Second (14–27.9 weeks)23,956 (33.10%)177 (34.20%)1,207 (7.20%)11 (10.10%)
  Third (28–40+ weeks)960 (1.30%)10 (1.90%)9 (0.10%)1 (0.90%)