Maternal serum inhibin A can predict pre‐eclampsia

OBJECTIVE: To compare median levels of maternal serum inhibin A in the second trimester blood samples of women who subsequently develop pre-eclampsia and those who do not. DESIGN: Retrospective analysis of 13 18 week samples from a bank of serum stored at -40 degrees C, originally taken for Down's syndrome screening. SETTING: Antenatal clinics in a teaching hospital. SAMPLE: Twenty-eight pregnancies with pre-eclampsia and 701 controls. Samples were taken, on average, 22 weeks before the diagnosis. MAIN OUTCOME MEASURE: Median inhibin A level. RESULTS: The median inhibin A level in the cases was 2.01 multiples of the gestation-specific median in the controls, a statistically significant elevation (P < 0.001). Twenty-three (82%) had levels above the normal median; 19 (68%), 15 (54%), and 11 (39%) exceeded the normal 75th, 90th and 95th centiles, respectively. CONCLUSIONS: In pre-eclampsia the maternal serum inhibin A level can be increased months before the onset of symptoms. This provides an opportunity to study the early natural history of the disease and possibly to conduct treatment trials.