Pregnancy and Graves Disease

[Threecitykids]

I have had a goiter on my neck for the past 5 years.  It does not bother me in the least.  It was discovered in 2003 when I was pregnant with my youngers son and was not given any medicine during the pregnancy.  The doctor had a biopsy on it and discovered that it is not cancereous.  Thankfully.  I am pregnant again and my new doctor has given me a perscription for PTU. M last blood test was last week and my T3 count is 2.43.  What is this number and what does it mean.  My worries are that I was told with the last one that the medicine can cause birth defects and I am worried for my child.  How safe is the medicine?  What is the worst that could happen if I do not take the PTU?  Will my child have Graves Disease?  I want the best for my child and I would like another opinion.  Not only do I have the goiter but I also have Diabetes.  What effects, if any, does the PTU have on my insulin?

[Mark Lupo, M.D.]

PTU is safe during pregnancy to treat hyperthyroidism -- the goal is to keep the T4 and T3 in the upper range of normal.  PTU crosses the placenta, but the risks to the child are low.  Most women in this situation are also followed by high-risk OB w/ frequent fetal ultrasound.  Hyperthyroidism can increase insulin requirements, PTU may help this.  Graves usually improves as the pregnancy progresses, so check levels frequently (every 4-5 weeks) and minimize the PTU dose needed.  Neonatal Graves is not common -- ask your doctor to check TSI level around week 24-28 -- if very elevated (> 3-5x upper normal) then there is a higher risk of baby having Graves.

T3 of 2.43 is hard to interpret w/o the reference range.  Would also be useful to look at the TSH and T4.