Table 3 Prevalence of select birth outcomes by self-reported electronic cigarette (e-cigarette) use and combustible cigarette smoking during the last 3 months of pregnancy among US women (N = 16,022)—Pregnancy Risk Assessment Monitoring Survey,* United States, 2016–2018.

From: Patterns of combustible and electronic cigarette use during pregnancy and associated pregnancy outcomes

Birth outcome

Former smokers (n = 8938)

E-cigarette only users (n = 189)

Dual users (n = 585)

Current smokers (n = 6310)

Preterm birth

 Unadjusted prevalence (%, 95% CI)†

7.7 (7.0, 8.4)

8.5 (5.5, 13.0)

8.3 (6.0, 11.4)

11.0 (10.0, 12.0)

 Adjusted prevalence (%, 95% CI)§

7.6 (6.9, 8.3)

9.2 (5.9,13.9)

9.6 (7.0, 12.9)

10.8 (9.8, 11.9)

 Unadjusted PR (95% CI)

0.70 (0.61, 0.80)

0.78 (0.50, 1.21)

0.76 (0.54, 1.06)

Reference

 Adjusted PR (95% CI)

0.70 (0.61, 0.81)

0.85 (0.55, 1.31)

0.88 (0.64, 1.22)

Reference

Small-for-gestational age

 Unadjusted prevalence (%, 95% CI)†

9.4 (8.5, 10.3)

11.5 (5.9, 21.1)

24.5 (19.2, 30.7)

19.7 (18.2, 21.3)

 Adjusted prevalence (%, 95% CI)§

9.3 (8.4, 10.2)

11.3 (5.8, 20.9)

24.1 (18.8, 30.4)

20.0 (18.5, 21.7)

 Unadjusted PR (95% CI)

0.48 (0.42, 0.54)

0.58 (0.30, 1.11)

1.24 (0.97, 1.59)

Reference

 Adjusted PR (95% CI)

0.46 (0.41, 0.53)

0.56 (0.29, 1.08)

1.20 (0.94, 1.55)

Reference

Low birthweight

 Unadjusted prevalence (%, 95% CI)†

6.3 (5.8, 6.8)

8.8 (5.8, 13.0)

11.3 (8.6, 14.6)

11.5 (10.7, 12.4)

 Adjusted prevalence (%, 95% CI)§

6.2 (5.7, 6.7)

9.4 (6.3, 13.9)

13.0 (10.0, 16.8)

11.7 (10.8, 12.6)

 Unadjusted PR (95% CI)

0.55 (0.49, 0.61)

0.76 (0.50, 1.15)

0.98 (0.74, 1.29)

Reference

 Adjusted PR (95% CI)

0.53 (0.47, 0.60)

0.81 (0.54, 1.21)

1.12 (0.85, 1.46)

Reference

  1. Bolded text indicates significant at p < 0.05.
  2. *PRAMS sites included in this analysis are: Alaska (2016–2018), Alabama (2017), Arkansas (2016), Colorado (2016–2018), Connecticut (2016–2018), Delaware (2016–2018), Georgia (2017–2018), Hawaii (2016), Iowa (2016–2017), Illinois (2016–2017), Kansas (2017–2018), Kentucky (2017–2018), Louisiana (2016–2018), Massachusetts (2016–2018), Maryland (2016–2017), Maine (2016–2017), Michigan (2016–2018), Missouri (2016–2018), Montana (2017), North Carolina (2017), North Dakota (2017), Nebraska (2016, 2018), New Hampshire (2016–2017), New Jersey (2016–2018), New Mexico (2016–2018), New York (2016–2017), New York City (2016–2018), Oklahoma (2016–2017), Pennsylvania (2016–2018), Rhode Island (2016–2018), South Dakota (2017–2018), Texas (2016), Utah (2016–2018), Virginia (2016–2018), Washington (2016–2018), Wisconsin (2016–2018), West Virginia (2016–2018), and Wyoming (2016–2018).
  3. †Unadjusted prevalence estimated from the weighted percentage and corresponding 95% confidence intervals.
  4. ‡Adjusted prevalence calculated as the average marginal predictive values.
  5. Unadjusted and adjusted prevalence ratio of birth outcome and corresponding 95% confidence interval. Adjusted prevalence ratios control for by maternal age, race/ethnicity, adequacy of prenatal care (based on the Adequacy of Prenatal Care Utilization (APNCU) Index), parity, multivitamin use, and presence of an obstetric risk factor.
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