The risk of preeclampsia rises with increasing prepregnancy body mass index.
OBJECTIVE
To explore the dose-dependent relation between prepregnancy body mass index (BMI) and the risk of preeclampsia after adjusting for measured confounders.


METHODS
We studied 1179 primiparous women who enrolled at < 16 weeks' gestation into a prospective cohort study of the pathogenesis of preeclampsia. Multivariable logistic regression was used to quantify the independent effect of prepregnancy BMI on the risk of preeclampsia after adjusting for race and smoking status. BMI was specified as a restricted quadratic spline.


RESULTS
Preeclampsia risk rose strikingly from a BMI of 15 to 30 kg/m(2). Compared with women with a BMI of 21, the adjusted risk of preeclampsia doubled at a BMI of 26 (odds ratio 2.1 [95% confidence interval, 1.4, 3.4]), and nearly tripled at a BMI of 30 (2.9 [1.6, 5.3]). Women with a BMI of 17 had a 57% reduction in preeclampsia risk compared with women with a BMI of 21 (0.43 [0.25, 0.76]), and a BMI of 19 was associated with a 33% reduction in risk (0.66 [0.50, 0.87]).


CONCLUSIONS
These results indicate that preeclampsia risk rises through most of the BMI distribution. The dramatic elevation in overweight prevalence in the United States may increase preeclampsia incidence in the future.
Bodnar
Lisa M
LM
Magee-Womens Research Institute, Pittsburgh, PA, USA. bodnar@edc.pitt.edu
Ness
Roberta B
RB
Markovic
Nina
N
Roberts
James M
JM
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D005260:Female; D006801:Humans; D009765:Obesity / Q000150:complications*; D010298:Parity; D010414:Pennsylvania / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology* / Q000209:etiology; D011247:Pregnancy; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors