Fertility — There are few data showing improved fertility outcomes in women with subclinical hypothyroidism treated with thyroid hormone. In observational studies of women with infertility and subclinical hypothyroidism, 44 to 84 percent of women treated with T4 successfully conceived during treatment.
In clinical trials of thyroid hormone replacement in patients with subclinical hypothyroidism undergoing assisted reproductive technologies (ART), treatment with T4 compared with placebo improved some pregnancy outcomes (eg, live birth rate, miscarriage rate)
Candidates for T4 replacement
Infertility or attempting pregnancy
We suggest initiating T4 replacement in women with subclinical hypothyroidism (TSH values above first trimester-specific normal reference range with normal free T4) who are trying to conceive and who have ovulatory dysfunction or infertility. This is consistent with Endocrine Society and ATA guidelines.
REF. UpToDate 2020.07.07
임신 1삼분기(trimester) TSH 0.1-2.5 mIU/L,
임신 2삼 분기 TSH 0.2-3.0 mIU/L
임신 3삼분기 TSH 0.3-3.5 mIU/L
임신 중 갑상선 기능저하증을 치료하는 데 있어 적절한 용량 조절 등을 위해 임신 16-20주까지 매 4주마다, 임신 26-32주 사이에 적어도 한 번 이상 TSH 와 유리T4를 측정합니다.
