SELFI study

Could Lipiodol affect the thyroid function of a mother and thyroid development of the baby?

Lipiodol is the iodine-rich contrast agent that is commonly used in infertility assessments such as the hysterosalpingogram (HSG) test for blocked Fallopian tubes. This study is investigating whether iodine affects the thyroid function of mothers, and thyroid development of the baby. SELFI stands for Safety and Efficacy of Lipiodol in Fertility Investigations.

What is this study trying to find out?

A hysterosalpingograms (HSG) test is a routine infertility assessment used to detect blocks in the fallopian tubes. Lipiodol is an oil soluble contrast agent that has been used in these assessments since the 1920s. Recent trials in the past two decades, such as the FLUSH
trial and H2O oil trial, showed an increased pregnancy rate of 30-40% in women with endometriosis and unexplained infertility. These studies made Lipiodol HSGs more popular.

However, Lipiodol has high iodine content and takes a long time to leave a woman’s body due to its long half-life of 50 days. An excess of iodine could possibly affect thyroid
function of women who undergo the procedure, as well as thyroid development of the
foetus - in the case of a successful pregnancy within few months of Lipiodol HSG.

To find out more, we are recruiting 200 women who plan to undergo Lipiodol HSG. We will monitor their iodine levels and thyroid function before the procedure and periodically for six months afterwards.

For women who become pregnant within six months of the HSG, once the baby is born, we will follow up the routine thyroid test that is done when baby is two days old, and do a repeat thyroid test of baby at seven days old. Thyroid function is assessed with a simple heel prick test.  

Why is this study important?

Lipiodol HSG is a routine infertility assessment that is frequently carried out due to the enhanced fertility benefits. However, it is essential to ensure the treatment is safe for both mum and baby. There are no prior large scale studies assessing the correlation between lipiodol retention, iodine excess and thyroid function following Lipiodol HSG. This research will help us to establish protocols for thyroid monitoring and treatment after Lipiodol HSG at a national and international level.

What does the study involve?


We're inviting women who plan to undergo a Lipiodol procedure as part of their infertility assessment to take part in this study.

If you take part, you'll need to provide an early morning urine and blood test to your nearest collection center in Auckland. After the HSG, you'll have eight blood tests and five urine tests over the following six months to check iodine levels and thyroid function.

If you take part in the study, you'll benefit from early detection of any thyroid problems, and - in consultation with the reproductive endocrinologist and respective fertility specialist - receive expert advice on your treatment options.


How do I find out more?

You can email the study team at or

You can also call us on 021 214 7975.