Background: Anemia during pregnancy is associated with oxidative stress, which might expectedly provoke harmful consequences on maternal and perinatal outcomes. Use of iron in women during pregnancy improves maternal hematologic parameters, while likely to worsen oxidative status. Objectives: Our study thus aimed to assess adverse outcomes on all women having been routinely iron supplemented during pregnancy. Methods: This is a prospective observational cohort of 74 pregnant women with singleton pregnancy whose baseline iron and oxidative status along with variations throughout pregnancy have been recently assessed at university clinics of Kinshasa, DR Congo. Obstetrical adverse outcomes were assessed according to the diagnosis of anemia and oxidative stress considered at recruitment, at 28-32 weeks of gestation and at term. For statistical calculations, we used t-test, chi-square test, ANOVAR and regression, the significance being stated at p < 0.05. Results: Complications significantly associated with anemia at the beginning of pregnancy were acute fetal distress (OR = 3.9, p < 0.03), prematurity (OR = 7.3, p < 0.007), low birth weight or LBW (OR = 3.4, p < 0.05), birth asphyxia (OR = 15.1, p < 0.002) and neonatal hypoglycemia (OR = 3, p < 0.05). When the diagnosis of anemia was considered at 28-32 weeks of gestation, significant associations were found with gestational diabetes mellitus or GDM (OR = 3.8, p < 0.05), cesarean section (OR = 4.8, p < 0.003), prematurity (OR = 5.3, p < 0.03), birth asphyxia (OR = 10.9, p < 0.008) and neonatal hypoglycemia (OR = 4.7, p < 0.02). At term, the diagnosis of anemia was significantly associated with GDM (OR = 9.2, p < 0.01), premature rupture of membranes or PROM (OR = 2.8, p < 0.05), cesarean section (OR = 6.03, p < 0.01), birth asphyxia (OR = 2.9, p < 0.05) and neonatal hypoglycemia (OR = 3, p < 0.05).