Gestational Age Specific Thyroid Function Reference Range

Chinese University of Hong Kong599 enrolled

Overview

It has been well accepted that maternal thyroid dysfunction has adverse affects on both mothers and fetuses. However, the dramatical changes during pregnancy make the interpretation of thyroid function test (TFT, i.e. free triiodothyronine \[FT3\], free thyroxine \[FT4\] and thyrotropin \[TSH\]) very difficult. Previous studies have shown that the level of thyroid hormones differs from non-pregnant population and varies from gestational ages. Moreover, studies have shown the agreement among different instrument platforms was quite low. This study is aimed to determine gestational age specific TFT reference ranges of the local pregnant population for all available platforms currently used under Hospital Authority and Department of Health.

Study Type

OBSERVATIONAL

Enrollment

599

Conditions

Thyroid Reference Values Pregnancy

Eligibility

Sex: FEMALEMin age: 16 YearsMax age: 50 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Pregnant women receiving pregnancy and postnatal care in the Department of Obstetrics \& Gynaecology, Prince of Wales Hospital, Hong Kong Exclusion Criteria: * 1\. Previous history of thyroid dysfunction (hypothyroidism or hyperthyroidism); * 2\. Autoimmune disease, particularly those receiving corticosteroid or immunosuppressant: e.g. systemic lupus erythematosus; * 3\. Disease associated with thyroid dysfunction: e.g. molar pregnancy

Outcomes

Primary Outcomes

Change of free triiodothyronine (FT3) during pregnancy

gestational FT3 level

Time frame: At the time of booking for antenatal visit (1st trimester), oral glucose tolerance test (24-32 weeks), admission for delivery (3rd trimester) and a gestational age assigned randomly.

Change of free thyroxine (FT4) during pregnancy

gestational FT4 level

Time frame: At the time of booking for antenatal visit (1st trimester), oral glucose tolerance test (24-32 weeks), admission for delivery (3rd trimester) and a gestational age assigned randomly.

Change of thyrotropin (TSH) during pregnancy

gestational TSH level

Time frame: At the time of booking for antenatal visit (1st trimester), oral glucose tolerance test (24-32 weeks), admission for delivery (3rd trimester) and a gestational age assigned randomly.