Aim: To study the levels of cancer antigen 125 (CA-125) in normal, preeclampsia, and gestational hypertension study groups and correlate with other parameters which mark the severity of the disease. Materials and methods: A cross-sectional study was conducted at a Tertiary Care Hospital, Mangaluru, India. A total of 165 subjects were divided into three study groups of preeclampsia, gestational hypertension, and normal pregnancy, and each group consisted of 55 subjects. Cancer antigen 125 levels were measured in these study groups. Results: Mean value of CA-125 value in the preeclampsia group was 56.7 IU/mL which was significantly higher compared to other two study groups. Cancer antigen 125 was found to have a positive correlation with systolic blood pressure (r value = 0.4, p value = 0.001), diastolic blood pressure (r value = 0.3, p value = 0.001), uric acid (r value = 0.2, p value = 0.001), and also an association was observed between increasing CA-125 and proteinuria (p value = 0.001) oligohydramnios (p value = 0.001) fetal growth restriction (p value = 0.03) and onset of the disease (p value = 0.001). However, a negative correlation with platelets (r value = −0.14, p value = 0.06) and birth weight (r value = −0.113, p value = 0.15) was observed. Conclusion: Cancer antigen 125 is a marker indicating increasing severity of the disease. It is a biochemical marker which can be used in screening of preeclampsia. Further studies are needed for the evaluation of raising serial CA-125 levels as a marker of progression of disease. Clinical significance: Hypertensive disorders of pregnancy are one of the most common causes of death due to pregnancy. Cancer antigen 125 was proposed to be elevated in patients with hypertension due to chronic inflammation. Hence CA-125 levels if used as screening tool can estimate the severity of the disease and help clinicians in identifying women who are at risk for further complications and act accordingly.