The effectiveness of ultrasound and s-βhCG measurement in predicting failure after medical abortion
Raquel Maciel, Maria Céu Rodrigues, Teresa Oliveira, Fátima Sousa, Lurdes Lima, Paulo Sarmento (Portugal)
Centro Hospitalar do Porto - Maternidade Júlio Dinis, Porto, Portugal
Objective. Diagnostic tests’ effectiveness in predicting failure after medical abortion has been subject of discussion in some studies. We compared ultrasound findings and β-hCG levels and tried to determine its cut-off value that would allow us to excuse a routine ultrasound examination as follow-up.
Methods.In 49 women who had opted to interrupt the pregnancy, with a mean gestacional age of 50 days, ultrasound examination and serum β-hCG were performed prior and around the 20th day after medical treatment. On the follow-up we considered as ultrasound findings the endometrial thickness – virtual or with heterogeneous content – the presence of an empty gestacional sac or an embryo arrest, and compared them with their corresponding s-hCG levels – its decrease %, its initial level % and its absolute final value.
Results.Treatment was successful in 92%. There was evidence of a close relation between ultrasound images and their β-hCG levels. The sensitivity of the ultrasound examination was 100% and its specificity was 49%. Despite the ratio of β-hCG initial level’s sensitivity, with a 1,3% cut-off, was the same as the one with a 0,8% cut-off (75%), the specificity of the first revealed to be more favorable (93,3% vs 86,6%).
Conclusion.The percentage of β-hCG initial level determination, combined with clinical examination, can be an effective method in predicting the success of the medical treatment, as an initial procedure. Therefore, ultrasonography should only be considered in prompt cases.