TABLE 1

Characteristics of Tdap-Unvaccinated and -Vaccinated Pregnant Women Who Delivered Children Born at KPSC, 2011–2014

CharacteristicsUnvaccinatedVaccinatedPa
n = 42 916 (%)n = 39 077 (%)
Maternal
 Age at delivery, y<.0001
  ≤258237 (19.2)6827 (17.5)
  26–3012 486 (29.1)11 573 (29.6)
  31–3411 902 (27.7)11 280 (28.9)
  ≥3510 291 (24.0)9397 (24.1)
 Race and/or ethnicity<.0001
  Non-Hispanic white11 127 (25.9)10 322 (26.4)
  Non-Hispanic African American3718 (8.7)2474 (6.3)
  Hispanic20 981 (48.9)18 789 (48.1)
  Non-Hispanic Asian American or Pacific Islander5947 (13.9)6375 (16.3)
  Other or multiracial1106 (2.6)1061 (2.7)
  Unknown37 (0.1)56 (0.1)
 Primary language.6554
  English39 525 (92.1)36 044 (92.2)
  Other2936 (6.8)2612 (6.7)
  Missing455 (1.1)421 (1.1)
 Needs interpreter1608 (3.7)1463 (3.7)<.0001
 Education<.0001
  Less than or equal to high school11 410 (26.6)9912 (25.3)
  Some college13 329 (31.1)11 402 (29.2)
  Bachelor’s degree10 792 (25.1)10 516 (26.9)
  Greater than or equal to master’s degree6888 (16.0)6744 (17.3)
  Unknown497 (1.2)523 (1.3)
Prenatal
 Medicaid insurance2489 (5.8)1947 (5.0)<.0001
 Parity<.0001
  016 184 (37.7)17 353 (44.4)
  115 616 (36.4)13 210 (33.8)
  ≥211 112 (25.9)8512 (21.8)
 Start of prenatal care<.0001
  ≤3 mo gestation39 911 (93.0)36 922 (94.5)
  >3 mo gestation2733 (6.4)1954 (5.0)
  No care or missing272 (0.6)201 (0.5)
 Received influenza vaccine18 272 (42.6)26 449 (67.7)<.0001
 Pregestational hypertension1583 (3.7)1256 (3.2).0002
 Pregestational diabetes829 (1.9)683 (1.7).0507
 Gestational diabetes6513 (15.2)6238 (16.0).0019
 Placenta previa and/or placental abruption2416 (5.6)2232 (5.7).6112
 Preeclampsia or eclampsia3514 (8.2)3139 (8.0).4162
Child
 Sex.0147
  Female20 886 (48.7)19 351 (49.5)
  Male22 030 (51.3)19 726 (50.5)
 Birth y<.0001
  201111 202 (26.1)8063 (20.6)
  201215 146 (35.3)5407 (13.8)
  201312 017 (28.0)8725 (22.3)
  20144551 (10.6)16 882 (43.2)
 Birth season<.0001
  Winter (January to March)10 191 (23.7)9056 (23.2)
  Spring (April to June)10 623 (24.8)9184 (23.5)
  Summer (July to September)11 688 (27.2)10 076 (25.8)
  Fall (October to December)10 414 (24.3)10 761 (27.5)
 Gestational age, wk (mean, SD)38.6 (1.98)38.9 (1.50)<.0001
 Preterm birth, <37 wk3855 (9.0)2235 (5.7)<.0001
 Birth wt, g (mean, SD)3328.0 (568.58)3369.5 (500.04)<.0001
  • a P values were calculated by using χ2 or Student’s t test and do not include missing or unknown values.