Clinical trial NCT04860622: Normal Range of TSH and FT4 in Pregnancy
Official title: Normal Range of TSH and FT4 in Pregnancy
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Hypothyroidism
Pregnancy Related
Thyroid
Dysfunction
Iodine Deficiency
Keywords: Hypothyroidism
Pregnancy
trimester
thyroid dysfunction
iodine level
Lead sponsor: Sehit Prof. Dr. Ilhan Varank Sancaktepe Training and Research Hospital
Sponsor class: OTHER
First posted: 2021-04-27
Enrollment: 528
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Turkish pregnant women living in Sancaktepe Region of Turkey

Brief summary: Physiological changes necessitate the use of pregnancy-specific reference ranges for thyrotrophin (TSH) and free T4 (FT4) to diagnose thyroid dysfunction during pregnancy. Although many centers use fixed upper limits for TSH of 2.5 or 3.0 mU/L, this may lead to overdiagnosis or even overtreatment.

The new guidelines of the American Thyroid Association have considerably changed recommendations regarding thyroid function reference ranges in pregnancy accordingly. Any hospital or physician that is still using the 2.5 or 3.0 mU/l cut-off for TSH during pregnancy should evaluate their own lab-specific cut-offs.

The investigator's objective is to establish a rational reference range of serum TSH for the diagnosis of subclinical hypothyroidism in the first, second, and third trimester of pregnant women in the Sancaktepe region in Turkey.

Detailed description: Serum thyroid function tests (including T3, T4, TSH, Anti-TPO) will be obtained from the singleton pregnancies in the first, second, and third trimester to determine the local specific normal ranges.

Eligibility criteria: Inclusion Criteria:

* Singleton pregnancy
* Free of pre-existing thyroid disease
* That do not use thyroid interfering medication
* That did not undergo IVF treatment
* TPOAb negative

Exclusion Criteria:

* Adolescent pregnancy
* Patient with pre-existing thyroid disease
* TPOAb positive
* Patient using thyroid interfering medication
* That had IVF treatment

Primary outcomes:
measure: TSH
timeFrame: On day 1
Secondary outcomes:
measure: free T4
timeFrame: On day 1
Other outcomes:
Locations:
city: Istanbul
country: Turkey
facility: Sehit Prof Dr Ilhan Varank Sancaktepe Training and Research Hospital
Study officials:
affiliation: Specialist
name: Murat Yassa, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H, Dosiou C, Grobman WA, Laurberg P, Lazarus JH, Mandel SJ, Peeters RP, Sullivan S. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017 Mar;27(3):315-389. doi: 10.1089/thy.2016.0457.
citation: Panesar NS, Li CY, Rogers MS. Reference intervals for thyroid hormones in pregnant Chinese women. Ann Clin Biochem. 2001 Jul;38(Pt 4):329-32. doi: 10.1258/0004563011900830.
citation: Donovan LE, Metcalfe A, Chin A, Yamamoto JM, Virtanen H, Johnson JA, Krause R. A Practical Approach for the Verification and Determination of Site- and Trimester-Specific Reference Intervals for Thyroid Function Tests in Pregnancy. Thyroid. 2019 Mar;29(3):412-420. doi: 10.1089/thy.2018.0439. Epub 2019 Feb 4.