Liver iron status and associated haematological parameters in relation to fetal growth and pregnancy outcome in rapidly growing adolescent sheep carrying a singleton lamb derived by embryo transfer.

Maternal and fetal liver iron concentrations and associated haematology parameters were determined in an adolescent sheep paradigm characterised by rapid maternal growth, premature delivery and feto-placental growth restriction. Singleton-bearing dams were offered a control or high dietary intake to induce normal or growth-restricted pregnancies, respectively. Pregnancies were terminated on Day 90 or 130 of gestation or progressed to term. Relative blood volume increased (P < 0.05) and liver iron concentration decreased (P < 0.003) from mid to late gestation in control, but not in high-intake dams. At 90 and 130 days gestation, liver iron concentrations were reduced (P < 0.001) in high-intake dams but fetal liver iron was independent of dam nutrition. High intakes leading to poor pregnancy outcome at term were characterised by increased maternal haematocrit, haemoglobin, total plasma protein, albumin (all P < 0.001) and serum iron (P < 0.05), and by reduced oestradiol 17β (P < 0.001) at Day 130. Thus, high dietary intakes that promote rapid maternal growth and adiposity are associated with early depletion of maternal liver iron stores and a relative failure of normal blood volume expansion, which may, in turn, underlie the reduction in uteroplacental blood flows and fetal nutrient delivery previously established for this paradigm.