TOTAL PLASMA FIBRONECTIN AS A MARKER OF PREGNANCY-INDUCED HYPERTENSIVE DISORDERS - A LONGITUDINAL-STUDY

Objective: To determine normal values of total plasma fibronectin in a ll three gestational trimesters and to examine 1) whether total plasma fibronectin levels differ between normotensive, hypertensive, and pre eclamptic women; and 2) whether total plasma fibronectin may serve as an early marker: of pregnancy-induced hypertensive disorders. Methods: Total plasma fibronectin was measured in 376 nulliparous women once i n each trimester of pregnancy. Normotensive controls (n = 222) and sub jects with pregnancy-induced hypertensive disorders (n = 154) were ide ntified after delivery. The group with pregnancy-induced hypertensive disorders was subdivided into a gestational hypertensive group (n = 12 5) and a preeclamptic group (n = 29). A complete total plasma fibronec tin data set was obtained from 347 subjects. Trends in total plasma fi bronectin values were compared for the different groups and relative r isks (RRs) were calculated after optimal cutoff levels had been determ ined by receiver operating characteristic curves. Results: Total plasm a fibronectin values (+/- standard error of the mean) were 227 +/- 3 m g/L in the first, 219 +/- 3 mg/L in the second, and 260 +/- 5 mg/L in the third trimesters in normotensive pregnancies. In the first trimest er and persisting throughout pregnancy, total plasma fibronectin level s were significantly higher in patients with pregnancy-induced hyperte nsive disorders than in controls and showed a sharper increase through out pregnancy. Increased first-trimester total plasma fibronectin leve ls result in an RR of 1.4 (95% confidence interval [CI] 1.1, 1.8) of d eveloping a pregnancy-induced hypertensive disorder in general. The RR for the development of preeclampsia was 1.7 (95% CI 0.9, 3.4), which was not significant, when the first-trimester total plasma fibronectin level was above the cutoff level of 240 mg/L. The RR for developing p reeclampsia was 3.8 (95% CI 1.8, 8.0) when the second-trimester total plasma fibronectin level increased above 230 mg/L. Conclusion: The fin dings of the present study confirm those of previous studies that have found increased total plasma fibronectin levels in pregnancy-induced hypertensive disorders. This study discovered that in these women, tot al plasma fibronectin levels are elevated in the first trimester. Tota l plasma fibronectin appears to be a poor predictor of preeclampsia wh en measured in a general pregnant population. Therefore, total plasma fibronectin should not be used as a routine screening test in a low-ri sk population. However, obstetricians may use total plasma fibronectin values to help determine the relative risk of developing pregnancy-in duced hypertensive disorders. (C) 1998 by The American College of Obst etricians and Gynecologists.