The effect of maternal iron status and intake during pregnancy on cardiovascular disease risk in the offspring

Iron is an important micronutrient essential in carrying oxygen and maintaining the function of many body enzymes. It is of particular importance during gestation as body demands increase leading to iron deficiency in women with inadequate iron stores at the start of pregnancy. Animal studies have shown that iron deficiency in pregnancy leads to offspring with adverse cardiovascular risk profiles compared to offspring of iron replete mothers. This thesis aimed to examine the association of maternal iron intake and status in pregnancy with short and long term birth outcomes that are considered cardiovascular risk indicators later in life.
Analysis of data from three cohorts and one Mendelian randomisation study was included in this thesis. Total maternal iron intake in early, but not late, pregnancy was positively associated with birth size. There was no evidence of association between taking iron-containing supplements in pregnancy and size at birth. However, taking multivitamin-mineral supplements, which contain iron, in late pregnancy was associated with an increased risk of preterm birth. Also taking iron supplements up to 32 weeks gestation was associated with lower offspring systolic blood pressure at 10 years. Maternal iron deficiency and anaemia in early pregnancy were associated with an increased risk of giving birth to a SGA baby. Infant brachio-femoral PWV measured at 2-6 weeks of age was found to be higher in women who were anaemic in early pregnancy, but not in those who were only iron deficient. Finally, using a Mendelian randomisation design, maternal iron status measured by serum ferritin with C282Y mutation as an instrumental variable, was not found to be associated with adult offspring BP and adiposity.
In conclusion, maternal iron intake and status in early pregnancy seem to be associated with short term birth outcomes like size at birth, while associations with long term offspring cardiovascular indicators were not detected in this thesis.