Pregnancy and Hypothyroid

[ANNU1980]

Problem: Married, Female, Age-29, Diagnosed with hyperthyroid. Doctor started PTU after about 6 weeks TSH increased and T3 decreased. Doctor has advised Thyroxine sodium - .050mg along with PTU. This block and replace therapy is hardly used so went for a second opinion from endocrinologist. The new doctor adviced to stop all medication and retest thyroid levels after 20 days.
During this time I have become pregnant with the current week being the 5th week. I have been now prescribed for 37.5mg thyroxin daily for 6 week and then a retest of thyroid levels. Just wanted to know if this the normal treatment followed for such cases and if any other prenatal vitamins are also required. Below here are the complete details with the values.

Test Report information in Dec 2007:
Free T4          : 26.13 pmol/L           Normal 11.5-22.7 pmol/L
Free T3(CLIA) :   4.3 pg/mL             Normal  2.4-4.2 pg/mL
TSH               : 0.16 ulU/ml             Normal  0.4-4.2 ulU/ml
      
Prescription by 1st doctor:
      - Tab PTU(50)  thrice daily for 3 months
      - Tab Inderal(10) twice daily
      - A re-laboratory test after 10 weeks

Retest done again after 10 weeks:

Test Report Information in March, 2008

Free T4          : 0.8 pg/mL              Normal 0.8-2.3 pg/mL
Free T3(CLIA) :   2.3 pg/mL            Normal  2.4-4.2 pg/mL
TSH               : 6.6  ulU/ml             Normal  0.4-4.2 ulU/ml

Prescription from March, 2008 by 1st Dr:
              --- Tab PTU(50) twice daily for 6 months
              --- Tab Thyroxin   Sodium 0.050 mg once daily for 3 months

Went for second opinion:

Advise: Stop all medication and thyroid levels to be retested after 20 days i.e on 9th April.

Current Situation:
Test report April, 2008

TSH :  7.0ulU/mL                                Normal: 0.3-5.5
Free T4 : 0.86ng/dL                                  Normal: 0.8- 2.3
Free T3 : 2.51pg/mL                                 Normal: 2.4-4.2

[ssm1981]

Good Morning Mark

This is SRM I am currently 24 weeks of pregnancy.

Diognised by low T4 the test result are below:

15th/March/2008
--------------------------
Investigation                Result       Free Range                       Status

Free T3                       5.57            3.20 - 6.8                  

                  
Free  T4                      8.59           10.30 - 34.700 pmol/L        Low

TSH                            1.97           0.40 - 4.20 m IU/L

My doctor advised to take Thyronorm 25 mcg for one month.


3rd /May/2008

Free  T4                      8.22           10.30 - 34.700 pmol/L      Low

TSH                            1.54           0.40 - 4.20 m IU/L

Still the T4 shows low Kindly advise me is it ok to continue the  same

thyronorm 25 mcg or need to increase the dosage currently running 24 th

week of prenancy.

Your advise on it will help me a lot.

Thanks in Advance

SRM

[Mark Lupo, M.D.]

With pregnancy, it is better to have a slightly low TSH than a slightly high one -- so the thyroxine makes sense -- it will be important to follow closely and keep the TSH roughly 0.3-2.0.  I don't see an indication for PTU at this point.  Would test thyroid antibodies to confirm this is auto-immune.  The other possibility is a temporary thyroiditis as the cause of the hyperthyroidism, now with a hypo phase -- but with pregnancy, better to treat with thyroxine then re-evaluate long-term need.

[ANNU1980]

Just one correction..The current medication is to take 37.5 micrograms of thyroxin daily