Table 2.
Risk ratios for preterm birth among pregnant persons with SARS-CoV-2 infection for trimester of infection and COVID-19 severity.
| [Total unweighted number of persons with available information] Weighted %a (95% CI) | |||||||
|---|---|---|---|---|---|---|---|
| Exposure | Total | Termb | Pretermc | Unadjusted RR | 95% CI | Adjusted RRd | 95% CI |
| Total | [6336] | 89 (87.4–90.6) | 11 (9.4–12.6) | ||||
| Trimester of SARS-CoV-2 infectione | [6336] | [5474] | [862] | ||||
| First | 13.9 (10.9–16.9) | 14.5 (11.1–17.8) | 9.4 (7–11.9) | 1 | ref. | 1 | ref. |
| Second | 39.5 (35.5–43.5) | 40.2 (35.8–44.6) | 33.7 (27–40.3) | 1.26 | (0.83–1.91) | 1.38 | (0.87–2.17) |
| Thirdf | 46.6 (42.5–50.7) | 45.3 (40.8–49.8) | 56.9 (50.1–63.6) | 1.8 | (1.22–2.65) | 1.84 | (1.26–2.69) |
| Severity of COVID-19 | [6336] | [5474] | [862] | ||||
| Mild | 57.3 (53.1–61.5) | 59.5 (54.8–64.2) | 39.7 (33.6–45.8) | 1 | ref. | 1 | ref. |
| Moderate-to-severe | 25 (20.8–29.3) | 25.3 (20.6–30) | 22.8 (16.6–29.2) | 1.32 | (0.89–1.97) | 1.01 | (0.71–1.46) |
| Critical | 3.5 (2.5–4.5) | 2.5 (1.6–3.4) | 12.0 (7.4–16.6) | 4.94 | (3.35–7.27) | 4.55 | (3.01–6.88) |
| Asymptomatic | 14.2 (11.2–17.1) | 12.8 (9.5–16) | 25.5 (18.5–32.4) | 2.6 | (1.75–3.85) | 2.57 | (1.71–3.86) |
| Severity of COVID-19 by trimester of SARS-CoV-2 infectione | |||||||
| First | |||||||
| Mild | 69.4 (55.9–82.9) | 70.6 (56–85.3) | 53.8 (41.3–66.4) | 1 | ref. | 1 | ref. |
| Moderate-to-severe | 23.2 (8.8–37.6) | 22.8 (7.2–38.4) | 28.6 (16.1–41) | 1.59 | (0.58–4.34) | 1.45 | (0.62–3.4) |
| Critical | -g | -g | -g | -g | -g | -g | -g |
| Asymptomatic | 6.5 (4.4–8.6) | 5.7 (3.7–7.7) | 16.3 (6.5–26) | 3.23 | (1.58–6.6) | 2.08 | (1.15–3.78) |
| Second | |||||||
| Mild | 57.2 (50.6–63.7) | 58.5 (51.3–65.6) | 44.2 (33.1–55.4) | 1 | ref. | 1 | ref. |
| Moderate-to-severe | 27.8 (21–34.7) | 29 (21.6–36.4) | 16.3 (10.9–21.7) | 0.76 | (0.47–1.22) | 0.86 | (0.52–1.4) |
| Critical | 3.9 (2–5.9) | 3.2 (1.4–4.9) | 11.6 (0–23.2) | 3.8 | (1.5–9.63) | 3.96 | (1.74–9.01) |
| Asymptomatic | 11.1 (7.9–14.3) | 9.3 (6.3–12.4) | 27.9 (13.5–42.3) | 3.25 | (1.74–6.07) | 3.36 | (1.75–6.43) |
| Thirdf | |||||||
| Mild | 53.9 (47.8–59.9) | 56.8 (49.9–63.8) | 34.7 (26.3–43) | 1 | ref. | 1 | ref. |
| Moderate-to-severe | 23.1 (17.6–28.7) | 22.7 (16.5–29) | 25.8 (15.8–35.8) | 1.73 | (0.97–3.07) | 1.07 | (0.64–1.78) |
| Critical | 3.9 (2.7–5.2) | 2.4 (1.1–3.6) | 14 (9.6–18.5) | 5.55 | (3.62–8.51) | 4.56 | (3.14–6.62) |
| Asymptomatic | 19.1 (13.5–24.6) | 18.1 (11.8–24.3) | 25.6 (17–34.1) | 2.08 | (1.21–3.6) | 2.05 | (1.23–3.42) |
COVID-19 coronavirus disease 2019, SARS-CoV-2 severe acute respiratory syndrome coronavirus 2, RR risk ratio, CI confidence interval, Ref referent group.
aPercentages may not sum to 100 due to rounding.
bInfant born at 37 to <43 weeks.
cInfant born at 22 to <37 weeks.
dAdjusted for age as a continuous variable,presence of one or more of the following underlying conditions: prepregnancy obesity, chronic lung disease, chronic hypertension, diabetes mellitus type 1 or 2, cardiovascular disease, immunosuppression, presence of gestational diabetes or hypertensive disorders of pregnancy.
eBased on date of first positive test.
fExcludes persons infected at ≥37weeks.
gSuppressed data due to unweighted total <25.