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. Author manuscript; available in PMC: 2020 Sep 9.
Published in final edited form as: Drug Alcohol Depend. 2018 Mar 29;187:72–78. doi: 10.1016/j.drugalcdep.2018.02.017

Table 2.

Unadjusted and adjusted linear regression results on birthweight and gestational age by marijuana use status during pregnancy.a

Birthweight (grams)
Mean birth weight (SE) Unadjusted mean difference (95% CI)b P-valuec Mean birth weight (SE) Adjusted mean difference (95% CI)d P-valuee
Nonusers (unweighted n = 8550) 3361.0 (6.4) Ref Ref 3364.3 (6.7) Ref Ref
Marijuana users (unweighted n = 463) 3291.7 (26.4) −69.3 (−122.6, −16.0) 0.011 3328.2 (28.8) −36.1 (−93.9, 21.8) 0.222
Gestational age (weeks)
Mean gestational age (SE) Unadjusted mean difference (95% CI)b P-valuec Mean gestational age (SE) Adjusted mean difference (95% CI)d P-valuee
Nonusers (unweighted n = 8550) 38.8 (0.02) Ref Ref 38.8 (0.02) Ref Ref
Marijuana users (unweighted n = 463) 39.0 (0.09) 0.15 (−0.03, 0.33) 0.112 38.9 (0.10) 0.12 (−0.08, 0.31) 0.236

SE: Standard error.

a

Includes Alaska (2009–2010), Hawaii (2009–2011), and Vermont (2009–2011) (unweighted n = 9013).

b

Mean difference using non-user as referent category.

c

P-value of t-statistic to assess statistical significance of mean difference using nonuser as referent category.

d

Mean difference using non-user as referent category, adjusted for age, race/ethnicity, marital status, education, number of previous live births, trimester of prenatal care initiation, pregnancy intention, pre-birth stressful life events, cigarette use during pregnancy, binge drinking during pregnancy, physical abuse, state, and infant birth year.

e

P-value of t-statistic to assess statistical significance of mean difference using nonuser as referent category, adjusted for previous described covariates.