Impact of maternal iron deficiency anaemia on fetal iron status and placental iron transporters in human pregnancy

Iron deficiency anaemia is associated with maternal morbidity and poor pregnancy outcomes. Placenta expresses both haem and non-haem iron transport proteins. The aim of the study is to examine the expression of placental iron trafficking molecules and associate them with maternal and neonatal iron status. Pregnant women who received prenatal care at the department of community health and development, Christian Medical College, Vellore, India for childbirth were recruited between 2016-2018. Pregnant women who were 18-35 years old with gestational age (GA) of [≥]36weeks were eligible to participate in the study. In a prospective cohort of pregnant women, 22% were iron deficiency anaemia (IDA) and 42% were iron replete. Pregnant women in the different groups were mutually exclusive. Samples were collected (Maternal blood, placental tissue, and cord blood) from pregnant women with gestational age of [≥]38 weeks at the time of delivery. Mean gestational age at first visit and delivery was 12.8{+/-}2.72 weeks and 39{+/-}1.65 weeks, respectively. Hemoglobin (9.3{+/-}0.9g/dl) and ferritin (15.4(0.8-28.3) ng/ml) levels at delivery were significantly decreased in IDA as compared to other groups. The foetal haemoglobin and ferritin levels were in the normal range in all groups. We further analysed the expression of iron transport genes in the placenta in the iron replete controls and the IDA group. Under maternal iron insufficiency, the expression of placental iron transporters DMT1 and FPN1 were upregulated at the transcriptional level. There was no correlation of maternal and cord blood hepcidin with foetal iron status in IDA. Thus, placental iron traffickers respond to maternal iron deficiency by increasing their expression and allowing sufficient iron to pass to the foetus.