The aim of our study was to investigate a possible correlation between the expression of the placenta-secreted hormones, β-subunit of human chorionic gonadotrophin (βhCG) and pregnancy-associated plasma protein A (PAPP-A), during the first trimester screening and the development of preeclampsia. A total of 155 patients between 11 + 0 and 13 + 6 weeks of gestation were enrolled in this study. PAPP-A and βhCG levels were measured using the KRYPTOR® system. The serum levels of βhCG were significantly higher in pregnancies which subsequently developed preeclampsia. The PAPP-A concentration did not differ significantly in pregnancies complicated by preeclampsia than in uncomplicated pregnancies. These results might contribute to developing new tests in the prediction of preeclampsia.