Mothers and Babies at Yorkhill Thyroid Health Cohort (MABY)

Iodine is a critical component of thyroid hormones, which are essential for normal growth, and brain development, most of the latter occurring during fetal life and in the first three years of life. Maternal dietary iodine is the sole source for fetuses and for exclusively breastfed infants. Recent evidence indicates that the UK female population is not iodine sufficient. Thus a significant proportion of UK pregnant women will also be insufficient in dietary iodine with potential harmful consequences for their babies. We wish to investigate the relationship between maternal iodine status (sufficient versus insufficient) in pregnancy, the mode of neonatal feeding (exclusively breast fed vs exclusively formula fed); and the effect this has on the functioning of the newborn baby's thyroid gland, with provision for later cognitive followup assessment. In order to do this, we will determine:

i) the iodine status of the mother during pregnancy and in the immediate postnatal period (dietary and urinary) and the newborn infant (urinary), ii) the thyroid function of the mother (thyroid stimulating hormone, thyroglobulin, T4 in serum during pregnancy, and thyroid stimulating hormone and thyroglobulin in dried blood spots postpartum) and infant (thyroid stimulating hormone in dried blood spots collected during a routine procedure).

Our hypothesis is that babies whose mothers are iodine insufficient will show higher levels of TSH and thyroglobulin than the babies of iodine sufficient mothers.