Plain English Summary
Background and study aims.
There is evidence from previous studies that low thyroid function during pregnancy may affect the intelligence quotient (IQ) of the child. However there have been no prospective studies to confirm this. We carried out a study to answer the question: Does testing thyroid function in early pregnancy and treating those women with underactive thyroids improve the IQ of their children?
Who can participate?
We recruited 22000 women pregnant with one baby (singleton pregnancies) before 16 weeks gestation who were not taking thyroid medication.
What does the study involve?
Blood samples were randomly allocated to a screen group and a control group. Thyroid testing was done immediately in all samples from the screen group. The control group samples were stored until the woman delivered the baby and the thyroid test was then carried out. Note: at the time of this trial (2002) there was no routine screening of thyroid function in pregnant women. The screen group women who were found to have an underactive thyroid received Levothyroxine daily for the length of the pregnancy. The control group received no treatment during pregnancy. The women who had an underactive thyroid diagnosed after delivery were referred to their general practitioner for standard care.
What are the possible benefits and risks of participating?
The women participating had a 50% chance of having thyroid function measured during early pregnancy (compared to 0% chance in normal practice). They then had the opportunity to see if the thyroxine intervention improved the IQ of their child compared to the children born to mothers from the control group. Side effects of thyroxine include palpitations and tiredness. Thyroid testing was done in women taking thyroxine 6 weeks after starting and again at 30 weeks of pregnancy. Less than 5% of women required a dose adjustment.
Where is the study run from?
The study was run from the University Hospital of Wales, Cardiff University. There were approximately 8 centres including one in Turin, Italy.
When is the study starting and how long is it expected to run for?
The study started in 2002 and ended in 2010.
Who is funding the study?
Wellcome Trust
Who is the main contact?
Professor JH Lazarus
Lazarus@cf.ac.uk
Trial website
Contact information
Type
Scientific
Primary contact
Prof John H Lazarus
ORCID ID
Contact details
Cardiff University
University Hospital of Wales
Professor of Clinical Endocrinology/
Heath Park
Cardiff
CF14 4XN
United Kingdom
+44 (0)29 20 742193
Lazarus@cf.ac.uk
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
065143
Study information
Scientific title
Randomised controlled trial of the effect of gestational thyroid hormone intervention therapy on childhood development
Acronym
CATS
Study hypothesis
Aim is to evaluate strategy of screening of thyroid function in early pregnancy.
Ethics approval
Trent Multi-Centre Research Ethics Committee, 24/06/2004, ref: MREC/04/4/026
Study design
Multicentre randomised controlled trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Other
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Childhood development
Intervention
Sera obtained from pregnant women before 16 weeks gestation. Sera randomised to 'screen' (T4 and Thyroid Stimulating Hormones [TSH] measured at time of randomisation) and 'control' (hormones measured post delivery) groups. Thyroxine intervention given to screen group with low T4/high TSH and to control group postpartum.
This is the only prospective randomised intervention trial of thyroxine in early pregnancy.
Intervention type
Other
Phase
Not Applicable
Drug names
Primary outcome measures
Intelligence Quotient (IQ) of children in screen and control groups.
Secondary outcome measures
No secondary outcome measures
Overall trial start date
01/06/2002
Overall trial end date
01/06/2010
Reason abandoned
Eligibility
Participant inclusion criteria
All pregnant women (aged 18 - 45 years) before 16 weeks gestation
Participant type
Patient
Age group
Adult
Gender
Female
Target number of participants
22,000
Participant exclusion criteria
1. Twin pregnancy
2. Thyroid treatment (T4 or antithyroid drugs)
Recruitment start date
01/06/2002
Recruitment end date
31/05/2006
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Cardiff University
Cardiff
CF14 4XN
United Kingdom
Sponsor information
Organisation
Cardiff University (UK)
Sponsor details
McKenzie House
Physical and Financial Resources
30-36 Newport Road
PO Box 497
Cardiff
CF10 3XR
United Kingdom
+44 (0)29 2087 9255
Arnoldc1@cardiff.ac.uk
Sponsor type
University/education
Website
Funders
Funder type
Charity
Funder name
Wellcome Trust (UK) (grant ref: GRO65143MA)
Alternative name(s)
Funding Body Type
private sector organisation
Funding Body Subtype
international
Location
United Kingdom
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Publication summary
2012 results in: http://www.ncbi.nlm.nih.gov/pubmed/22316443
Publication citations
-
Results
Lazarus JH, Bestwick JP, Channon S, Paradice R, Maina A, Rees R, Chiusano E, John R, Guaraldo V, George LM, Perona M, Dall'Amico D, Parkes AB, Joomun M, Wald NJ, Antenatal thyroid screening and childhood cognitive function., N. Engl. J. Med., 2012, 366, 6, 493-501, doi: 10.1056/NEJMoa1106104.