Relation between single serum progesterone assay and viability of the first trimester pregnancy

OBJECTIVE This study was designed to detect the relation between serum progesterone and viability of pregnancy during the first trimester. MATERIAL AND METHODS Two hundred and sixty women during the first trimester of their pregnancies were hospitalised due to vaginal bleeding and/or abdominal pain and were included in this study. Criteria for inclusion in this study were: certain dates, foetus conceived spontaneously with no history of infertility and a positive serum pregnancy test. Blood samples were taken from women included in this study for serum progesterone assay; the patients were followed by ultrasound until the end of the first trimester for the viability of the pregnancy and the outcome of their pregnancy was recorded. RESULTS BY THE END OF THE FIRST TRIMESTER, WOMEN INCLUDED IN THIS STUDY WERE CLASSIFIED INTO: viable pregnancy group (n=178; 68.5%) and non-viable pregnancy group (ended by miscarriage) (n=82; 31.5%). The mean serum progesterone of the studied population was significantly higher in the viable pregnancy group (46.5±7.4 ng/mL) compared to non-viable pregnancy group (9.9±4.8 ng/mL; p<0.05). The serum progesterone cut-off level of 10 ng/mL was 79.3% sensitive for diagnosing non-viable pregnancy and 93.3% specific for the diagnosis of viable pregnancy, while a cut-off level of 20 ng/mL was 95.1% sensitive for the diagnosis of non-viable pregnancy and 98.9% specific for diagnosing viable pregnancy. CONCLUSION Serum progesterone is a reliable marker for early pregnancy failure and a single assay of its serum level can differentiate between viable and non-viable pregnancies.