Inclusion criteria and an invitation to join us

The number of clinical studies on the effects of thyroid function on fertility and pregnancy is increasing rapidly. However, there are still unanswered clinically important questions such as whether women with mild thyroid function test abnormalities or thyroid peroxidase antibody (TPOAb) positivity preconception or during pregnancy can benefit from levothyroxine treatment. While various randomized trials have been performed, these have not always been able to either include the most up to date definition of thyroid function test abnormalities, or to investigate currently recognized high-risk subgroups, or to translate recent insights from human physiology and observational studies into study designs (1,2). In an effort to overcome such limitations, we have now extended the Consortium of Thyroid and Pregnancy to include randomized trials with the aim to combine data and perform individual participant data meta-analyses. 

The initial aim of Consortium on Thyroid and Pregnancy was to create a formal platform for collaboration that can facilitate high quality studies on the clinical consequences of thyroid function test abnormalities or thyroid autoimmunity on fertility, pregnancy or child outcomes. Currently, the consortium consists of 23 prospective cohort studies with data on close to 100.000 mother-and-child pairs. We have recently published our first study (3) and five other studies are currently ongoing.

Through this letter, we would like to invite anyone that has observational data available (published or unpublished) to join the pre-existing Consortium on Thyroid and Pregnancy, and join currently ongoing studies. Furthermore, we would like to invite anyone with data available from randomized trials (published or unpublished) to join the new randomized trial arm of the Consortium on Thyroid and Pregnancy for the set-up of new studies to further add to knowledge gaps in this field of research. At the bottom of this letter, the inclusion criteria for various types of data that can contribute to the Consortium on Thyroid and Pregnancy can be found. We hope you can join our efforts to advance evidence-based medicine in the field of thyroid, fertility and pregnancy within the Consortium on Thyroid and Pregnancy.

If you wish to participate, or require more information, please contact us via e-mail.

 

Correspondence to: Tim I.M. Korevaar
Room Na-2913, Department of Epidemiology and Endocrinology, Erasmus Medical Center
Postbus 2040, 3000 CA
Rotterdam, The Netherlands
E-mail: t.korevaar@erasmusmc.nl

 

 

Inclusion criteria for participation in the consortium

 

For population-based cohorts for studies on thyroid outcomes
- Non-selected or population-based prospective cohorts.
- Serum TSH, or FT4 or thyroid antibodies measured in pregnant women (any gestational age).
- Disease-specific prospective cohorts can be included for specific studies when deemed relevant.
- Data on thyroid medication usage to identify potential bias.

For population-based cohorts for studies on pregnancy or child outcome
- Non-selected or population-based prospective cohorts.
- Serum TSH, or FT4 or thyroid antibodies measured in pregnant women (any gestational age).
- Follow-up complete until the end of pregnancy or beyond.
- Disease-specific prospective cohorts can be included for specific studies when deemed relevant.
- Cohorts in which women received treatment will be excluded, unless this is part of the research question.

For randomized trials
- Selected women with either subclinical hypothyroidism, isolated hypothyroxinemia or thyroid antibodies.
- Randomized to treatment or a control group consisting either of no treatment or placebo.
- Follow-up complete until the end of pregnancy or beyond.
- Disease-specific prospective cohorts can be included for specific studies when deemed relevant.