Objective
To investigate whether an appropriate combination of maternal serum inhibin A, free &bgr;-human chorionic gonadotropin (free &bgr;-hCG), unconjugated estriol (uE 3), and alpha-fetoprotein (AFP) may be an effective means of screening for pre-eclampsia in the second trimester of pregnancy.
Setting
Women who attended an antenatal clinic in Oxford, from whom serum samples were stored, 19 of whom subsequently developed pre-eclampsia.
Methods
Serum inhibin A, free &bgr;-hCG, uE 3, and AFP were measured in 32 serum samples collected from the 19 women who developed pre-eclampsia and, for each sample, in three control samples collected from women with unaffected pregnancies matched for gestational age and maternal age.
Results
In pregnancies that developed pre-eclampsia the median inhibin A value was raised (1.7 multiples of the median (MoM) for unaffected pregnancies (95% confidence interval (95% CI) 1.1 to 2.7 MoM), the median free &bgr;-hCG was raised (2.1, 1.4 to 3.3 MoM) and the median uE 3 was lowered (0.8, 0.6 to 0.98 MoM) after 19 completed weeks of gestation and at least 2 weeks before the onset of proteinuria. Values of AFP were similar in affected and unaffected pregnancies. Combining the values of inhibin A, free &bgr;-hCG, and uE 3 to form a screening test would detect an estimated 55% of affected pregnancies with a false positive rate of 5%.
Conclusions
Inhibin A, free &bgr;-hCG, and uE 3 in combination may be a useful screening test during the second trimester for pre-eclampsia.
