Evidence for distinct preterm and term phenotypes of preeclampsia.

Objective: To determine differences in maternal and fetal characteristics in pregnancies complicated by preterm versus term preeclampsia.

Methods: Using our electronic database we identified 143 women who met the American College of Obstetricians and Gynecologists criteria for preeclampsia between January 1995 and August 2003. We collected data on age, smoking status, maternal serum markers, and newborns. We compared the group delivering preterm (<37 weeks) with those delivering at term (> or =37 weeks). Analyses were based on ANOVA, Wilcoxon Rank Sum test, and chi-square test. Statistical significance was determined based on alpha = 0.05. Data are expressed as mean +/- SD unless otherwise indicated.

Results: Eighty women delivered preterm and 63 delivered at term. Women who delivered preterm with preeclampsia were younger, lighter, and were more likely to smoke cigarettes than those delivering at term with preeclampsia. Maternal liver enzyme concentrations were significantly greater in the preterm group. Newborn birthweight percentile (gestational age specific) was significantly lower for preterm preeclampsia. We found no significant differences in maternal platelet count, uric acid concentration, or newborn gender between groups.

Conclusions: Differences exist in maternal and fetal characteristics between women who develop preterm preeclampsia and those who develop preeclampsia at term. These data support the hypothesis that multiple preeclamptic phenotypes exist.