This project took place at our London centre which operated between 1995 and 2021.
Why do we need this research?
Iodine is an important nutrient that pregnant women need to help their babies’ brains develop properly. Low iodine levels during pregnancy can lead to problems for the child later in life, such as difficulty with speech and reading. Iodine deficiency can also lead to health problems for women.
There’s some evidence to suggest that many women don’t get enough iodine in their diet during pregnancy. However, we don’t know the true extent of iodine deficiency among pregnant women or fully understand how iodine levels might change during pregnancy.
What’s happened in this project?
Researchers funded by Tommy’s looked at data from a study called UPBEAT, which involved more than 1,500 pregnant women with obesity,to find out more about iodine deficiency during pregnancy. These women donated blood and urine samples throughout their pregnancy. By looking at nearly 1,000 urine samples donated early in the second trimester of pregnancy (15–18 weeks), our researchers found that 70% of the obese women in this study were iodine deficient. They also found that women who had lower levels of iodine in their urine were more likely to have babies with a lower birthweight.
Our researchers are now looking at the iodine status of obese pregnant woman in another way. Although the amount of iodine in urine is a useful measure of recent iodine intake, it may not accurately reflect iodine intake over a long period of time. A better alternative is to measure the amount of thyroglobulin – a protein that is produced exclusively by the thyroid gland – in blood, as this reflects longer-term iodine intake; levels of thyroglobulin are higher when iodine levels are low as the thyroid has to work harder to compensate for the lack of iodine. Our researchers are therefore looking at data from 400 obese pregnant women who took part in the UPBEAT study to find out how many had high levels of thyroglobulin in a blood sample that was taken when they were 15–18 weeks pregnant.
What difference will this project make?
This study is providing a detailed picture of iodine deficiency in obese pregnant women and has shown that it is linked to lower birthweight. The findings from this research could strengthen recommendations that pregnant women should make sure they get enough iodine in their diet or could lead to trials of iodine supplements during pregnancy.
