This Case Conference reviews the normal changes in thyroid activity that occur during pregnancy and the proper use of laboratory tests for the diagnosis of thyroid dysfunction in the pregnant patient. TSH levels decreased gradually at weeks 5 to 6 to the lowest point at weeks 9 to 12 range 007 328 mUL.

Why Your Thyroid Hormone Levels May Be Fluctuating

As a result the normal thyroid-stimulating hormone TSH level during pregnancy is lower.

Normal tsh in pregnancy. After hCG mediated hyperthyroidism the most common pathological cause of hyperthyroidism in pregnancy is autoimmune Graves disease. Reference ranges remain controversial but for most people the normal range falls between 04 and 40 mUl. Thyroxine at increasing dosages until TSH is brought to a normal-low range.

This lowers the risk of the TSH elevating in the first trimester. I have biochemical pregnancy last year. The dosage should be adjusted every four weeks until the TSH level is stable.

The starting dose is usually 010-015 mgday and should be adjusted according to TSH levels every four weeks. 02 to 30 mUL. SCH is defined as a serum TSH between 25 and 10 mIUL with a normal FT4 concentration.

Importantly 90 of all upper limits of TSH are higher than the recommended fixed TSH cutoff concentrations of 25 and 30 mUL for the first and second trimesters respectively. Workup of Thyroid Abnormalities Clinically Indicated Testing Test TSH first. If the thyroid TSH levels are low hyperthyroidism is instead a most likely diagnosis.

Knowing that pregnancy impacts reference ranges for thyroid lab tests some associations have created new reference ranges specifically for women who are pregnant. Guidelines for TSH Levels During Pregnancy TSH should be kept below 25 mIUL prior to conception. Majority of women in US have sufficient intake.

Overall the most common cause of hypothyroidism is the autoimmune disorder known as Hashimotos thyroiditis see Hypothyroidism brochure. The size of the gland increases by 10. 01 to 25 mUL.

For non-pregnant women the TSH upper normal limit is typically 42 to 45 mIUL 7. During the first trimester the TSH level should be maintained at a level of between 01 and 25 mIUL. Gurmukh Singh answered 48 years experience Pathology.

Is this is a reason i am not able to get pregnant from past 2 years. Many practitioner especially when fertility and pregnancy are concerned prefer to see TSH levels less than 2. This is followed by a rise back to an intermediate value at weeks 15 to 19 range 129 329 mUL.

Women with a TSH concentration above the trimester-specific reference interval with a decreased FT4 and all women with a TSH concentration above 100 mIUL irrespective of the level of FT4 are also considered to have OH. Standard TSH levels during Pregnancy. The typical range of reference for TSH levels is anywhere between 045 and 45 milliunits per liter mUL.

In the course of a normal pregnancy TSH may be low in the first trimester when human chorionic gonadotropin hCG peaks. In this context a normal fT4 generally excludes hyperthyroidism 14 20. Production of thyroid hormones T3 and T4 increases by about 50.

3 LOW TSH. Reflex to free T4 plus total T3 for hyperthyroidism Free T4 is normal. Approximately 25 of women will have a TSH of greater than 6 mIUL slightly elevated and 04 will have a TSH greater than 10 mIUL during pregnancy.

02 to 30 mUL. Serum TSH is very sensitive to minor changes in thyroid hormone concentrations in serum. Normal TSH ranges can vary widely depending on a persons age sex and body weight.

Hypothyroidism in pregnancy is treated with a larger dose of thyroxine than in the non-pregnant state. For both hormones a wide range of reference interval values has been reported with the upper limit of TSH varying between 215 and 468 mUL between different cohorts. Hypothyroidism in pregnant women is treated with levothyroxine in a sufficient dosage to return the TSH level to normal.

Pathological causes of low TSH in pregnancy may include multiple gestation hyperemesis gravidarum and molar pregnancy 14. Normal TSH range levels are between 03 and 30 and when the thyroid is assumed to be functioning well. A woman in the 18th week of pregnancy presented with tachycardia increased blood pressure severe vomiting increased total and free thyroid hormone concentrations a.

All reports are normal. TSH high or low abnormal. Thyroid disease is subclinical and does not warrant further workup.

To establish normative range of TSH in each trimester of pregnancy To establish normative range of f T3 and f T4 in each trimester of pregnancy and to know the prevalence of subclinical hypothyroidism in normal pregnancies.