Objective. Investigation of the relationship between the first trimester complete blood count parameters and miscarriage. Materials and Methods. The study group consisted of 39 patients who admitted to the hospital with the diagnosis of abortus imminens between January 2016 and December 2019, and whose pregnancy ended as miscarriage before the 20th week. The control group consisted of 200 randomly selected healthy pregnant women, with follow-up and delivery in our hospital. Patient information was obtained retrospectively from the hospital records. Results. Age and BMI of both groups were similar. There was no significant difference between the two groups in terms of basophil, neutrophil, eosinophil, lymphocyte, monocyte, platelets, RBC, hemoglobin, hematocrit, MCV, MCH, MCHC, RDW, MPV, Pct and PDW, while leukocyte and neutrophil counts was statistically significantly higher in the miscarriage group (p=0,002, p=0,001, respectively). NLR was statistically higher in the miscarriage group (p=0,005), PLR was also higher in the miscarriage group, but this did not reach statistical significance (p=0,056). Both groups were similar in terms of MLR. Conclusions. High NLR levels obtained from the hemogram results in the first trimester seems to be associated with miscarriage. NLR can be an easy, cheap and useful tool for predicting pregnancy prognosis in patients with abortus imminens.