AIMS

This study aims to investigate the affect of iodine and sodium status throughout pregnancy on outcome of the offspring.

HYPOTHESIS

Iodine is required for the production of thyroid hormones which have a role in brain and neurological development during gestation and early life. The mother is an important source of thyroid hormones to the developing fetus particularly before the fetus is able to produce its own. Mild to moderate maternal iodine deficiency has been associated with a reduction in IQ and psychomotor development in the offspring and has also been linked to the development of ADHD. Excessively high or low intake of sodium throughout pregnancy can have adverse effects on both the mother and the offspring and therefore maternal sodium levels will also be analysed in the urine. Measuring iodine and sodium levels in maternal urine throughout pregnancy and analysing against offspring outcome will identify the most influential period of development on which iodine and sodium have an affect.

EXPOSURE VARIABLE

All maternal urine samples from each trimester

OUTCOME VARIABLE

Iodine, sodium and creatinine levels. Creatinine will be analysed to correct for urine volume.

CONFOUNDING VARIABLES

maternal age at delivery, mother's parenting score, HOME score, family adversity index, life-event score, intakes of omega-3 fatty acids and iron

child factors

sex, birthweight, preterm birth, breastfeeding, and ethnic origin

maternal factors

smoking status, alcohol intake, parity, maternal depression since birth and use of fish-oil supplements during pregnancy

markers of socioeconomic status

maternal and paternal education, housing status and crowding