Table 1.
Selected Demographic Characteristics of Patients With Pregnancies Ending in Stillbirth (n = 795) and Matched Live Births (n=3,180)
| Characteristic | Stillbirths | Live Births | P* |
|---|---|---|---|
| Age at delivery (y) | 30.6 (14–49) | 30.4 (14–46) | .01 |
| Maternal age 35 y or older | 218 (27.4) | 633 (19.9) | <.001 |
| Gestational age at prenatal care initiation (wk) | 7.5 (5–30) | 7.4 (5–37) | .59 |
| Maternal comorbidity† | 108 (13.6) | 123 (3.9) | <.001 |
| Pregnancy complication‡ | 365 (45.9) | 218 (6.86) | <.001 |
| Gestational age at 1st vaccination (wk) | 17.6 (2–39)§ | 17.4 (2–39)∥ | .64 |
| Tobacco smoking during pregnancy | 57 (7.2) | 279 (8.8) | .002 |
| Nulliparous | 238 (29.9) | 974 (30.6) | .38 |
| History of stillbirth | 40 (5.0) | 54 (1.7) | <.001 |
| Black non-Hispanic | 107 (13.5) | 234 (7.4) | <.001 |
| Prepregnancy obesity | 279 (35.1) | 584 (18.4) | <.001 |
Data are mean (range) or n (%) unless otherwise specified.
P-values calculated by χ2 tests for categorical variables and Wilcoxon median two-sample test for continuous variables.
International Classification of Diseases, Ninth Revision codes for maternal diabetes, systemic lupus erythematosus, thyroid disorders, hypertension, cardiovascular disease cholestasis, renal disease, and sickle cell disease in the 6 months before pregnancy through vaccination date or index date (stillbirth outcome date or reference date for matched control).
International Classification of Diseases, Ninth Revision codes for maternal infections, placental complications, amniotic cavity or membrane problems, fetal growth restriction, maternal trauma, and uterine rupture during current pregnancy and before vaccination date or index date.
Vaccinations received in 51.7% of pregnancies ending in stillbirth.
Vaccinations received in 52.9% of pregnancies ending in live birth.