2ND-TRIMESTER SERUM-FREE BETA-HUMAN CHORIONIC-GONADOTROPIN LEVELS AS A PREDICTOR OF PREECLAMPSIA

Background. To prospectively assess maternal serum free beta human cho rionic gonadotrophin (beta hCG) estimation between 15 and 18 weeks ges tation, as a screening test for preeclampsia in primigravid women. Met hods. A prospective longitudinal study in a University Teaching Hospit al. The study population was 430 primigravid women, who had maternal s erum free beta hCG levels measured as part of antenatal serum screenin g for Down's Syndrome in the second trimester, who booked consecutivel y within the unit and went on to deliver on the unit's labor ward. The se women were followed during their subsequent pregnancy and categoriz ed into those who remained normotensive and those who developed pre-ec lampsia on both clinical and biochemical grounds. The beta hCG levels were used to construct a receiver operator characteristics curve (ROC) to assess the screening potential for pre-eclampsia. Results. Ninetee n (4.4%) women in the study group developed pre-eclampsia. The median second trimester free beta hCG multiples of the median (MOM) was signi ficantly elevated compared to that of the control group (1.52 vs 1.10, p=0.03). The ROC curve shows that for a sensitivity of 79%, the speci ficity was only 54%. Conclusions. Maternal serum free beta hCG alone m easured in the second trimester is not clinically useful as a screenin g test for pre-eclampsia in primigravid women. It has, however, some p redictive value.