Table 3.

Examination of potential interaction effects between maternal smoking and preeclampsia and gestational hypertension combined, preeclampsia, or gestational hypertension, and fetal growth

Model	Unadjusted β (95% CI)	P value	Adjusted βa (95% CI)	P value
Model 1b - Preeclampsia and gestational hypertension combined z-score = smoker (y/n) + (preeclampsia + gestational hypertension) + interaction term
Smoker	−0.25 (−0.50, 0.01)	0.06	−0.26 (−0.53, 0.004)	0.05
(Preeclampsia + gestational hypertension)	−0.14 (−0.28, −0.01)	0.04	−0.17 (−0.31, − 0.03)	0.02
Smoker*(Preeclampsia + gestational hypertension)	0.05 (−0.28, 0.37)	0.78	0.05 (−0.27, 0.37)	0.76
Model 2 - Preeclampsia z-score = smoker (yes/no) + preeclampsia+ interaction term
Smoker	−0.25 (−0.49, 0.003)	0.05	−0.24 (−0.50, 0.02)	0.07
Preeclampsia	−0.33 (−0.49, −0.18)	<0.0001	−0.37 (−0.53, −0.21)	<0.0001
Smoker*Preeclampsia	−0.003 (−0.37, 0.36)	0.98	−0.02 (−0.38, 0.35)	0.93
Model 3 - Gestational Hypertension z-score = smoker (yes/no) + gestational hypertension+ interaction term
Smoker	−0.25 (−0.49, 0.002)	0.05	−0.25 (−0.51, 0.01)	0.06
Gestational hypertension	0.08 (−0.08, 0.24)	0.31	0.03 (−0.13, 0.20)	0.70
Smoker*Gestational hypertension	0.04 (−0.32, 0.39)	0.85	0.04 (−0.32, 0.40)	0.81

^aAnalysis adjusted for age (continuous) and BMI (continuous)

^bIn model 1, preeclampsia and gestational hypertension subjects were combined into one category and compared to controls

Referent groups: smoking (y/n) - nonsmokers; (Preeclampsia + gestational hypertension) - controls;