Guidelines for TSH Level in Pregnancy With Reference Range

Q: Follow-up of a hypothyroid patient trying to get pregnant.


Since you are positive for AMA, just remember that you are prone to be hypothyroid after getting pregnant. Presence of AMA in one’s body increases the risk of repeated autoimmune disturbances.

You understand that thyroid hormone is very important both for maternal and fetal health. The baby also depends totally on the mother for its hormonal needs during early pregnancy. So there should be adequate thyroxine in your body during pregnancy to meet the total hormonal needs. Also, excess of this hormone is again poisonous for the fetus just as its scarcity. So, we have to keep thyroid hormones in the right concentration throughout pregnancy. For that, TSH monitoring is done. High TSH means the active hormone is less.

All you have to do is to follow the TSH guidelines strictly both before and after getting pregnant.

Guidelines for TSH Levels During Pregnancy

  • TSH should be kept below 2.5 mIU/L prior to conception. This lowers the risk of the TSH elevating in the first trimester.
  • During the first trimester, the TSH level should be maintained at a level of between 0.1 and 2.5 mIU/L
  • 0.2 to 3.0 mIU/L during the second trimester
  • 0.3 to 3.0 mIU/L in the third trimester

This will be done by continuous team work of your gynecologist and an endocrinologist. Conceive on a low TSH level, say 1.5mlU/L or so. After getting pregnant, your TSH levels will definitely increase. This would be suggestive that the active thyroid hormone in your body is in low amounts. Your doctor will increase your medication. TSH monitoring will be done in every 4 weeks (monthly). This way the doctor will be able to keep the levels within the desirable range and react to the changes accordingly.

Usually after first trimester, the dose of medication is reduced. The baby also starts making its own hormone.

Also take care of your diet. Hypothyroid women are likely to be deficient in calcium reserve. Discuss taking multivitamin and multi mineral supplements with your doctor.

With careful monitoring, you can have a safe and healthy pregnancy.

Take Care,

Buddy M.D.

Medical Advice (Q&As) on “Guidelines for TSH Level in Pregnancy With Reference Range

  1. Hend Kamel

    Hey my sister has hypothyroidism (taking thyroxine 50 ) and now she is pregnant (1st trimester), Her TSH is 6.71 ulU/ml , so what is the dose required to reach the normal level ? They said to raise the thyroxine dose from 30-50%

    1. Buddy M.D. Post author

      Thyroxine needs to be increased with regular monitoring of TSH levels till she attains the desired levels. This needs to be done under the guidance of a doctor.

      They may ask her to increase the dose by 30%.

  2. Pravin

    my wife is pregnant ( 1st trimester ). her tsh is 0.22. Let me know it is ok or not as per nornal rang TSH in pregnency.

  3. Tanu

    Hello Dr.
    i m preganat 7 weeks now my reports tsh level is 4.5 is it dangerous ??? why its range 2.5 below can u explain

    1. Buddy M.D. Post author

      Indicates that you are slightly hypothyroid. Need to be on thyroid pills. This is essential for both, you and your baby.

    1. Buddy M.D. Post author

      TSH levels don’t tell about pregnancy. Value is high and needs correction according to your age and health status.

  4. Ali

    Hello Dr.,. My wife is 8 weeks pregnant, her TSH level is 4.62 and doctor suggested to take thyronorm 100mg daily.Is it sufficient or shall we increase dose?. For last 2yrs she is using thyronorm 75mg daily.
    Thanks ,. Ali

    1. Buddy M.D. Post author

      You may start with this prescribed dose to begin with. Your doctor would test her levels again, shortly after therapy begins, to check the results. If the TSH levels become normal, the dose is alright, otherwise, an increase may be considered.

    1. Buddy M.D. Post author

      The idea is to bring back your TSH level within absolute normal range. Dose is customized according to the patient.

      Dose is usually higher in most cases.

  5. Michelle

    I am 10 weeks pregnant and my TSH is 0.19. I know that is in range but on the lower side. I am on 50mcg of levothyroxine q day and 2x a week am on 100mcg of levothyroxine. Do you think my levels need to be adjusted.

    1. Buddy M.D. Post author

      Appears alright for new. However, continuous monitoring of your TSH levels would be essential as your pregnancy progresses.


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