A Retrospective Assessment of Prevention and Treatment of Iron Deficiency Amongst Patients Requiring Peripartum Transfusion

Background: Iron deficiency is common and affects nearly 18% of pregnant women in the United States. This is attributable to both poor baseline stores in young women and the high iron requirements of pregnancy; a singleton pregnancy results in a net loss of 630 mg of iron. Both maternal and fetal outcomes are impacted by iron deficiency. There are higher rates of maternal postpartum depression, fetal growth restriction, prematurity and developmental delay when mothers are iron deficient in pregnancy. It is also important to avoid transfusions in women of child bearing age, due to the risks of alloimmunization and hemolytic disease of the newborn. Since iron deficiency is the most common cause of anemia in pregnant women, we sought to assess the prevalence of iron deficiency in women receiving peripartum red blood cell transfusions.

Materials and Methods: This study is a retrospective quality review of all cases of peripartum transfusion at an academic centre caring for high risk pregnancies from January 2013 to July 2018. All women admitted to the Labor and Delivery ward who received a red blood cell transfusion were identified through electronic blood bank database. We also identified the next age-matched woman to deliver who was not transfused. Charts were reviewed for risk factors for iron deficiency, evidence of prior iron deficiency, iron supplementation during pregnancy and fetal outcomes such as birth weight, gestational age at delivery, NICU admission and fetal mortality. A detailed transfusion history was recorded for women who received peripartum transfusions, including peritransfusion hemoglobins and indication for transfusion. Results: To date, 120 cases of peripartum red blood cell transfusion have been reviewed. Of these, 19 patients were excluded due to chronic anemia unrelated to iron deficiency or pregnancy (e.g., chronic renal failure). Age matched controls have been identified and are pending review. Preliminary data suggests that the majority of red cell transfusions given in the peripartum period are to women experiencing antepartum (26%) and/or postpartum (63%) hemorrhage. Thirty seven percent of women who were transfused had documented anemia in pregnancy and 51% of women were iron deficient in pregnancy (ferritin <30 ng/mL). Twenty one percent of women in the transfused group were noted to have pre-existing iron deficiency before conceiving. In the transfused cohort, six patients were identified as having alpha thalassemia trait (3 cases) or beta thalassemia minor (3 cases).

Discussion: We present the preliminary results of a retrospective review of cases of peripartum red cell transfusion at an academic centre. Although a significant portion of transfusions were unavoidable and attributable to hemorrhage, it may be possible to decrease the number of units these women require. Over half of women who were transfused had documented iron deficiency in pregnancy. This raises the question of how many units of red blood cells could have been saved by appropriately treating these patients' iron deficiency. It is also clear in the literature that iron deficiency is associated with multiple poor fetal and maternal outcomes; we have identified an opportunity to improve the care of these women and their babies. We plan to feed this information back to the Obstetrical caregivers at our centre and to help educate providers about the recognition and treatment of iron deficiency in pregnancy. The high rate of transfusion amongst patients with alpha thalassemia trait and beta thalassemia minor warrants further investigation, but may highlight a knowledge gap around transfusion triggers for these patients.