Prophylactic Iron Supplementation in Pregnancy and its Implications in Development of Pre-eclampsia: A Case-control Study

Abstract

Introduction: Pre-eclampsia is a serious complication of pregnancy and is associated with increased maternal and perinatal morbidity and mortality. Increased iron and ferritin concentration is associated to a higher risk of pre-eclampsia and prophylactic iron supplementation can sometimes be harmful to pregnant women who are otherwise not iron deficient. Aim: To analyse serum iron, serum ferritin, serum Transferrin Receptor (sTFR) levels, Total Iron Binding Capacity (TIBC) among iron supplemented pre-eclamptic cases and normotensive pregnant controls. Materials and Methods: This prospective, observational, case- control study was conducted in Jaipur National University Institute of Medical Sciences and Research Centre (JNUIMSRC), Jaipur, Rajasthan, India for a period of one year from (February 2019-January 2020). A total of 200 pregnant females, all on iron supplementation during the course of their pregnancy, 100 in pre-eclampsia group (case group); 100 in normotensive group (control group), in third trimester and between 18- 45 years of age were enrolled in the study. Serum iron, serum ferritin, sTFR and TIBC were estimated using fully automated analysers. Results: Median Interquartile Range (IQR) of serum ferritin levels in cases were higher than the controls [41 (30-70) vs 24 (17-44); p<0.001]. Serum ferritin in cases were also found to correlate positively with systolic (r=0.37, p=0.001) Blood Pressure (BP) whereas TIBC correlated negatively with diastolic BP (r=-0.238, p-value=0.017). The median IQR differences of TIBC values among cases and controls were insignificant {485 (404-523) vs 493 (448- 544)} and differences of median IQR of sTFR values among cases and controls were significant {8.5 (7-9) vs 8.9 (8-10)}. Subjects with serum feritin levels >40 ng/mL had three times increased risk of PE (Odds ratio=3, 95% Cl=1.571-5.157). Conclusion: Elevated serum ferritin, decreased sTFR levels and correlation of Ferritin and TIBC to BP in pre-eclampsia compels us to put cautionary remarks over testing these parameters before continuing with iron supplements. This may prevent a possible iron related added complications in pre-eclampsia and help clinicians decide about restricting/lowering iron supplement doses in case a situation of iron overload arise.