Controlled Antenatal Thyroid Screening study

ISRCTN	ISRCTN46178175
DOI	https://doi.org/10.1186/ISRCTN46178175
Secondary identifying numbers	065143

Submission date: 22/07/2005
Registration date: 22/07/2005
Last edited: 12/06/2015

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Nutritional, Metabolic, Endocrine

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

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

Contact information

Prof John H Lazarus
Scientific

Cardiff University
University Hospital of Wales
Professor of Clinical Endocrinology/
Heath Park
Cardiff
CF14 4XN
United Kingdom

Phone	+44 (0)29 20 742193
Email	Lazarus@cf.ac.uk

Study information

Study design	Multicentre randomised controlled trial
Primary study design	Interventional
Secondary study design	Randomised controlled trial
Study setting(s)	Other
Study type	Treatment
Participant information sheet	Not available in web format, please use the contact details below to request a patient information sheet
Scientific title	Randomised controlled trial of the effect of gestational thyroid hormone intervention therapy on childhood development
Study acronym	CATS
Study objectives	Aim is to evaluate strategy of screening of thyroid function in early pregnancy.
Ethics approval(s)	Trent Multi-Centre Research Ethics Committee, 24/06/2004, ref: MREC/04/4/026
Health condition(s) or problem(s) studied	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
Primary outcome measure	Intelligence Quotient (IQ) of children in screen and control groups.
Secondary outcome measures	No secondary outcome measures
Overall study start date	01/06/2002
Completion date	01/06/2010

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Sex	Female
Target number of participants	22,000
Key inclusion criteria	All pregnant women (aged 18 - 45 years) before 16 weeks gestation
Key exclusion criteria	1. Twin pregnancy 2. Thyroid treatment (T4 or antithyroid drugs)
Date of first enrolment	01/06/2002
Date of final enrolment	31/05/2006

Locations

Countries of recruitment

United Kingdom
Wales

Study participating centre

Cardiff University

Cardiff
CF14 4XN
United Kingdom

Sponsor information

Cardiff University (UK)
University/education

McKenzie House
Physical and Financial Resources
30-36 Newport Road
PO Box 497
Cardiff
CF10 3XR
Wales
United Kingdom

Phone	+44 (0)29 2087 9255
Email	Arnoldc1@cardiff.ac.uk
Website	http://www.cardiff.ac.uk/index.html
"ROR"	https://ror.org/03kk7td41

Funders

Funder type

Charity

Wellcome Trust (UK) (grant ref: GRO65143MA)
Private sector organisation / International organizations

Location: United Kingdom

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
Publication and dissemination plan	Not provided at time of registration
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	09/02/2012		Yes	No