THE ROLE OF A SINGLE FREE BETA-HUMAN CHORIONIC-GONADOTROPIN MEASUREMENT IN THE DIAGNOSIS OF EARLY-PREGNANCY FAILURE AND THE PROGNOSIS OF FETAL VIABILITY

This prospective controlled study investigated the concentrations of f ree beta-human chorionic gonadotrophin (HCG) subunit in 554 women with a singleton intrauterine or tubal pregnancy, They presented with vagi nal bleeding and/or abdominal pain in the first 18 weeks of pregnancy, The control group comprised 156 women with musculoskeletal pain and n o vaginal bleeding. Their pregnancies continued to term. The study gro up comprised 398 women (141 threatened-continuing pregnancies, 37 thre atened-miscarriages, 185 non-continuing pregnancies and 35 tubal pregn ancies), Free beta-HCG concentrations were significantly lower in the non-continuing, threatened-miscarriage and tubal pregnancy groups [mea n 4.62, 6.50 and 4.27 ng/ml respectively; 95% confidence interval (CI) 3.75-5.69, 4.46-9.48 and 2.92-6.2 respectively] than in the control a nd threatened-continuing groups (mean 41.61 and 48.22 ng/ml respective ly; 95% CI 34.53-50.13 and 42.03-55.32 respectively) (P < 0.001 in all cases), A cut-off value at 20 ng/ml was found to differentiate betwee n the 'viable' (control and threatened-continuing) and the 'abnormal'' (non-continuing, threatened-miscarriage and tubal) pregnancies, with 88.3% sensitivity and 82.6% positive predictive value, An excellent di agnostic and prognostic usability of free beta HCG was confirmed by a receiver operating characteristic curve plot, In conclusion, a single serum free beta-HCG measurement taken in early pregnancy is valuable i n the immediate diagnosis of early pregnancy failure and the long-term prognosis of viability.