Predictive value of serum β-hCG for early pregnancy outcomes among women with recurrent spontaneous abortion

Abstract Objective To examine peak serum levels of the β-subunit of human chorionic gonadotropin (β-hCG) for prediction of early pregnancy outcomes among women with recurrent spontaneous abortion (RSA). Methods In a retrospective study, the medical records of pregnant women with a history of RSA treated at Sun Yat-sen Memorial Hospital, China, between January 2011 and July 2013 were reviewed. Serum β-hCG had been measured twice weekly from 5 to 13 weeks of pregnancy, and pregnancy was monitored by transvaginal ultrasonography to 13 + 6  weeks. Optimal cutoff for peak β-hCG level was determined by receiver operator characteristic curve analysis and Youden index. Women were divided into four groups on the basis of optimal peak β-hCG cutoff and pregnancy outcome (pregnancy at 13 weeks or spontaneous abortion). Peak β-hCG levels and length of pregnancy at this peak were examined. Results Overall, 1240 patients were included. The optimal cutoff value of peak β-hCG was 88 468 IU/L, with a sensitivity, specificity, positive predictive value, and negative predictive value for successful pregnancy of 95.6%, 88.0%, 95.6%, and 89.0%, respectively. A faster rise in β-hCG, higher peak β-hCG, and longer pregnancy length at peak β-hCG were associated with successful early pregnancy. Conclusion A cutoff value of serum β-hCG of 88 000 IU/L could be used to predict early pregnancy outcomes for women with a history of RSA.