Table 4.

Thyroid Screening of Pregnant Women Receiving L-Thyroxine Therapy

1. 10 of 91 women with TSH>4.0 mU/L and positive thyroid antibodies
(TPOAb and/or TGAb) during pregnancy were receiving daily levothyroxine.
2. Screening results:
TPOAb and TGAb positive:	4
TPOAb only positive:	5
TGAb only positive:	1	The TSH value was 8 mU/L.
3. TSH values>3 mU/L:	5
5. TSH values<3 mU/L:	5	All were positive for TPOAb.
Recommendation35,37: Women on levothyroxine prior to pregnancy should increase their dose by 30% or more as soon as pregnancy is confirmed and arrange for a TSH test to assure adequacy of the dose during pregnancy.