Background: Preeclampsia is one of the most serious complications of pregnancy, leading to various maternal and fetal complications. Objectives: This study aimed to determine the effect of oral esomeprazole in the treatment of preeclampsia in pregnant mothers. Methods: In this double-blind clinical trial, we compared oral esomeprazole with a placebo. The study population included 120 pregnant women with preeclampsia (60 in the esomeprazole 40 mg group and 60 in the placebo group) who were referred to Ba'ath Hospital in Sanandaj in 2023. Patient care and follow-up were conducted from the time of diagnosis of preeclampsia and inclusion in the study groups until delivery and the final condition of the baby. The outcomes investigated included prolongation of pregnancy and maternal, fetal, and neonatal outcomes. Results: The average delivery time in the esomeprazole group was 37.3 ± 1.2 weeks, compared to 37.5 ± 1.7 weeks in the placebo group, with no statistically significant difference (P = 0.75). The frequency of maternal outcomes, such as eclampsia, pulmonary edema, hemolysis, placental abruption, renal failure, hepatic hematoma, ascites, thromboembolism, and maternal death, was not statistically different between the esomeprazole and placebo groups, and no severe complications were observed in either group. Similarly, fetal outcomes, including intrauterine growth restriction (IUGR) and changes in fetal heart rate patterns, did not significantly differ between groups, with no instances of fetal or neonatal death observed. Additionally, neonatal outcomes, such as Apgar scores below 7, NICU admissions, mechanical ventilation, and other severe neonatal complications, were not significantly different between the two groups (P > 0.05). Although the esomeprazole group showed a lower frequency of adverse maternal, fetal, and neonatal outcomes compared to the placebo group, these differences were not statistically significant. Conclusions: The frequency of adverse maternal, fetal, and neonatal outcomes was lower in the esomeprazole group than in the placebo group for most variables, but the differences were not statistically significant. Therefore, it cannot be concluded with certainty that esomeprazole is ineffective in preventing or controlling preeclampsia.