Figure 2. Primary and negative control analysis showing associations between maternal alcohol intake and smoking during pregnancy, as well as partner's alcohol use and smoking during pregnancy, and maternal HDP, gestational hypertension and preeclampsia.

Association between alcohol and smoking during pregnancy in mothers and partners. One category increase in maternal alcohol intake (nondrinker, low to moderate or heavy drinker), is associated with a decreased odds of developing hypertensive disorder of pregnancy (HDP) in both the complete case cohort and the negative control cohort, both adjusted and mutually adjusted models (mutually adjusted odds ratio, 0.86; [95% CI, 0.77–0.96]). Similarly, partner's drinking (in the same increasing levels as described for maternal alcohol intake) is associated with a decreased odds of HDP in the adjusted and mutually adjusted model. Any maternal smoking during pregnancy (smoker or nonsmoker) shows a strong negative association with HDP in all cohorts and models, as compared with no smoking; partner's smoking during pregnancy, however, is not associated with maternal HDP risk when mutually adjusting for maternal smoking. *Adjusted for age, body mass index, smoking (in the alcohol model), alcohol (in the smoking model), parity, race or ethnicity, educational attainment, and marital status (maternal or partner covariates depending on the exposure model). ^†Mutually adjusted for all covariates in the adjusted models plus mother/partner alcohol intake/smoking (depending on the exposure model).