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.