Scientific Evidence Portal
The puzzling association between smoking and hypertension during pregnancy | Zhang J, Klebanoff MA, Levine RJ, Puri M, Moyer P
Article Published: 1999
Risk: RR = 0.6 for gestational hypertension; 0.5 for preeclampsia
Significance: Statistically Significant Negative
Published By: Am J Obstet Gynecol. 1999 Dec;181(6):1407-13
"After we controlled for prepregnancy body mass, age, socioeconomic status, and race,
both past smoking and smoking during pregnancy were associated in a dose-response pattern with reduced risks of gestational hypertension and preeclampsia. For women who smoked >/=10 cigarettes/d the relative risks with respect to women who had never smoked were 0.6 (95% confidence interval, 0.4-0.9) for gestational hypertension and 0.5 (95% confidence interval, 0.4-0.7) for preeclampsia. This protective effect was observed both for mild and severe gestational hypertension and for preeclampsia. The more and the longer a woman had smoked previously, the lower was her risk of development of hypertension during pregnancy."
" This association could not be explained by confounding factors, by changes in placental morphologic or histopathologic characteristics, by maternal net weight gain, or by elevated liver enzyme bioactivity."
"Conclusion: Smoking is associated with a reduced risk of hypertension during pregnancy. The protective effect appears to continue even after cessation of smoking."
Emphases added above. The title of this study speaks volumes about the prejudice and the superstition against smoking and the effect of tobacco on health, and betrays the ideology that tobacco is “only evil” and “only harmful.” The “puzzling,” in fact, can only exist with a prejudice in place, and not with a truly scientific and open mind. Furthermore, the benefits of smoking on health have been known for centuries, and long before the scientific era.