INTRODUCTION: There exists a prevailing concern regarding the heightened susceptibility of women with a solitary kidney to unfavorable consequences during pregnancy. Irrespective of the underlying etiology, individuals with a solitary kidney are advised to have regular annual screenings for blood pressure and urinalysis due to their increased susceptibility to developing proteinuria, hypertension, and renal failure. OBJECTIVE: To investigate the risk of adverse pregnancy outcomes in women with a maternal solitary kidney by comparing maternal and fetal outcomes to those of healthy pregnant women. METHODS: This retrospective, single-center study was conducted with 29 pregnant women with maternal solitary kidney and 60 healthy controls at a tertiary hospital. Obstetric data such as gestational hypertension, preeclampsia, preterm labor, birth week, mode of delivery, Apgar scores, and neonatal intensive care requirements, were compared between the groups. A binary logistic regression analysis was performed to determine the obstetric complications increased by the presence of maternal solitary kidney. RESULTS: The number of spontaneous abortions, serum creatinine and blood urea nitrogen levels were significantly higher in the patients with solitary kidney (p <
0.05). The birth week was earlier among the patients with a solitary kidney compared to the controls (p = 0.013). The preterm and cesarean delivery rates were also higher in the case group (p = 0.002 and p = 0.035, respectively). The pregnant women with solitary kidney were found to have higher rates of gestational hypertension, preeclampsia, and maternal intensive care requirements (p = 0.008, p = 0.015, and p = 0.008, respectively). Logistic regression analysis revealed a seven-fold increase in the rate of preterm labor (1.45-37.64) and a three-fold increase in preeclampsia (1.27-22.08) among the pregnant women with a solitary kidney. CONCLUSION: Patients with solitary kidney are at high risk of encountering pregnancy complications, such as gestational hypertension, preeclampsia, and preterm labor. These pregnant women should be followed up carefully, starting from the first prenatal visit.