Background: Pre-eclampsia is a major public health issue. Current screening methods are based on maternal characteristics and medical history, but complex predictive models combining different clinical and biochemical markers have been proposed. However, although their accuracy is high, the implementation of these models in clinical practice is not always feasible, especially in low- and middle-resource settings. CA-125 is a tumoral marker, accessible and cheap, with proven potential as a severity marker in the third trimester of pregnancy in pre-eclamptic women. Assessment of its use as a first-trimester marker is necessary.Methods: This observational study involved fifty pregnant women between 11 and 14 weeks of pregnancy. Clinical and biochemical markers (PAPP-A), known for their value in pre-eclampsia screening, were recorded for every patient as well as first-trimester value of CA-125 and third-trimester data regarding blood pressure and pregnancy outcome.Results: No statistical correlation between CA-125 and first-trimester markers was observed except with PAPP-A, with which it exhibited a positive correlation. Additionally, no correlation was made between it and third-trimester blood pressure or pregnancy outcomes.Conclusions: CA-125 first-trimester values do not represent a valuable marker for pre-eclampsia screening. Further research on identifying an accessible and cheap marker to improve pre-eclampsia screening in low- and middle-income settings is needed.