Smoking before pregnancy and risk of gestational hypertension and preeclampsia.
OBJECTIVE
Our purpose was to determine whether smoking before pregnancy reduces the risk of gestational hypertension or preeclampsia.


METHODS
The trial of Calcium for Preeclampsia Prevention (CPEP) was a randomized study of 4589 nulliparous women conducted in 5 US medical centers during the years 1992 through 1995. Women were classified into 4 exposure groups by smoking history obtained at study enrollment (13-21 weeks' gestation): (1) never smoked, (2) smoked but quit before the last menstrual period (LMP), (3) smoked but quit after LMP but before enrollment, and (4) smoked and still smoking at enrollment.


RESULTS
After adjustments were made for maternal age, race, body mass index, type of health insurance, and clinical center, women smoking at enrollment had a reduced risk of hypertension (relative risk = 0.8; 95% CI, 0.6-0.9). Women who quit smoking before the LMP did not have reduced risk (relative risk = 1.1; 95% CI, 0.9-1.3). Results were similar for gestational hypertension and preeclampsia examined separately.


CONCLUSIONS
Women who smoke but quit before becoming pregnant do not have a reduced risk for gestational hypertension or preeclampsia.
England
Lucinda J
LJ
Division of Epidemiology, Statistics, and Prevention Research, National Institute of Child Health and Human Development, Bethesda, MD 20892-7510, USA.
Levine
Richard J
RJ
Qian
Cong
C
Morris
Cynthia D
CD
Sibai
Baha M
BM
Catalano
Patrick M
PM
Curet
Luis B
LB
Klebanoff
Mark A
MA
D000328:Adult; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D011225:Pre-Eclampsia / Q000209:etiology*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000209:etiology*; D018570:Risk Assessment; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation