Role of Serum β-hCG and First Trimester Ultrasonographic Parameters in Predicting Mid-trimester Pregnancy Outcomes: A Prospective Cohort Study

Abstract

Introduction: One of the concerns in pregnant women is the risk of miscarriage and the psychological sequelae that follow. Screening in early pregnancy can identify future miscarriages in asymptomatic pregnancies. Aim: To study the role of serum Beta-Human Chorionic Gonadotropin (β-hCG) doubling and ultrasonic parameters like Yolk Sac Diameter (YSD), Gestational Sac Diameter (GSD), and Crown-Rump Length (CRL) in predicting mid-trimester pregnancy outcomes. Materials and Methods: A prospective cohort study was conducted at SRM Medical College and Hospital in Tamil Nadu, India, among 381 antenatal women between 6-10 weeks of gestation for a period of two years from December 2017 to July 2019. At baseline, parameters like serum β-hCG doubling titer at 48 hours and ultrasound parameters like YSD, GSD, and CRL were evaluated. The participants were followed-up until 20 weeks of gestation. The results were statistically analysed using sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV). Results: The mean age of the women included in the study was 25.89±4.2 years, with the majority of women belonging to the 21-29 years age group. Among the enrolled pregnant women, 347 had normal outcomes while 34 experienced pregnancy failure. The results indicated that β-hCG was the strongest predictor of pregnancy outcomes with a sensitivity of 52.9%, specificity of 100%, PPV of 100%, and NPV of 95.6%. YSD predicted loss rates with a sensitivity of 50%, specificity of 97.1%, PPV of 62.9%, and NPV of 95.2%. GSD predicted miscarriage with a sensitivity of 17.6%, specificity of 97.4%, PPV of 40%, and NPV of 92.3%. CRL predicted miscarriage with a sensitivity of 30.5%, specificity of 97.9%, PPV of 61.1%, and NPV of 93.2%. Conclusion: β-hCG, YSD, GSD, and CRL were found to be statistically significant in predicting abnormal pregnancy outcomes. Among the four, β-hCG proved to be the best predictor.