Second-trimester maternal serum inhibin A concentration as an early marker for preeclampsia

OBJECTIVE: Maternal serum inhibin A concentration is elevated in established preeclampsia. The aim of this study was to investigate whether this relationship antedates the appearance of the classic signs of preeclampsia. STUDY DESIGN: A retrospective analysis was performed on trisomy 21 screening data from 685 women at between 15 and 19 weeks' gestation. The main outcome measures were preeclampsia and small for gestational age (<5th percentile) infants. RESULTS: Preeclampsia developed in 35 women (5.5%). Women with inhibin A concentration >2.0 multiples of the median were significantly more likely to acquire preeclampsia (P < .00001) and to be delivered of a small for gestational age infant (<5th percentile, P < .00001) than were women with inhibin A concentration less than or equal to 2.0 multiples of the median. The odds ratios were 9.4 (95% confidence interval 4.6-19.3) for development of preeclampsia and 18.2 (95% confidence interval 6.0-54.8) for preeclampsia necessitating delivery at <37 weeks' gestation. The association remained statistically significant for nulliparous women. CONCLUSION: Elevated maternal inhibin A concentration in the second trimester was strongly associated with a subsequent risk of preeclampsia. The potential role of second trimester inhibin A measurement in a screening strategy for preeclampsia needs to be investigated further.