Iron deficiency and anemia are common after bariatric surgery. Women have a higher risk of developing such long-term complications. Though oral supplementation is indicated, intravenous iron therapy is required in some cases. This retrospective study included patients who underwent bariatric surgery between 2012 and 2018. Postoperative anemia patients receiving parental iron therapy were assessed during the first 24months. Their baseline characteristics, surgery type, and laboratory test results were analyzed. A follow-up analysis included a subgroup of women with and without gynecological disorders. Patients with vitamin B12 or folic acid deficiencies were excluded. Six hundred eleven (63.3%) met the inclusion criteria: 525 underwent gastric bypass, of which 79.6% were women. Overall, postoperative anemia was 28.9% (24.5% related to gastric bypass), especially among women (84%). Anemia refractory to oral iron therapy was observed in 12.9% of patients. All the patients requiring iron infusions (n = 54) were women, and half of them (51.8%) reported abnormal uterine bleeding. Postsurgical hemogram values were significantly lower in patients with abnormal uterine bleeding (despite the same number of infusions) than in those without gynecological disorders; 89.2% of these women had preoperative anemia. Anemia is frequent in bariatric surgery patients despite supplementation. Women undergoing gastric bypass with a history of gynecological disorders are prone to require more iron infusions. Consulting with the patient about a higher risk is important, and probably knowing the plan or including the opinion of an OBGYN to determine as a team the assessment, treatment, and prognosis.