2021 European Thyroid Association Guideline on Thyroid Disorders prior to and during Assisted Reproduction

Abstract

Severe thyroid dysfunction may lead to menstrual disorders and subfertility. Fertility problems may persist even after restoring normal thyroid function, and then an assisted reproductive technology (ART) may be a solution. Prior to an ART treatment, ovarian stimulation is performed, leading to high oestradiol levels, which may lead to hypothyroidism in women with thyroid autoimmunity (TAI), necessitating levothyroxine (LT4) supplements before pregnancy. Moreover, women with the polycystic ovarian syndrome and idiopathic subfertility have a higher prevalence of TAI. Women with hypothyroidism treated with LT4 prior to ART should have a serum TSH level <2.5 mIU/L. Subfertile women with hyperthyroidism planning an ART procedure should be informed of the increased risk of maternal and foetal complications, and euthyroidism should be restored and maintained for several months prior to an ART treatment. Fertilisation rates and embryo quality may be impaired in women with TSH >4.0 mIU/L and improved with LT4 therapy. In meta-analyses that mainly included women with TSH levels >4.0 mIU/L, LT4 treatment increased live birth rates, but that was not the case in 2 recent interventional studies in euthyroid women with TAI. The importance of the increased use of intracytoplasmic sperm injection as a type of ART on pregnancy outcomes in women with TAI deserves more investigation. For all of the above reasons, women of subfertile couples should be screened routinely for the presence of thyroid disorders.

MANAGEMENT OF ENDOCRINE DISEASE: Thyroid and female infertility: more questions than answers?!

“…TgAb can be added systematically or when not allowed according to the local regulatory authorities in women with TSH levels >2.5 mIU/L and no increased TPOAb levels. Treatment with LT4 is suggested in infertile women with TAI and serum TSH >2.5 mIU/L on a case-by-case basis and systematically if TSH levels are >4.0 mIU/L or the ULRR (16).…”

“…However, evidence proving that LT4 can lead to spontaneous pregnancy in women with (overt) hypothyroidism is rather anecdotic and probably only effective in case of ovarian dysfunction and not when male infertility, endometriosis or tubal obstruction are the cause of infertility (15). Recent guidelines on thyroid and infertility recommend starting LT4 treatment promptly in case of overt thyroid dysfunction and when TSH values are >4.0 mIU/L/the upper limit of the reference range (ULRR) (16).…”

“…LT4 treatment may be considered for TSH levels >2.5 mIU/L with TAI and should be started for TSH levels >4.0 mIU/L or >ULRR. In the recent ETA guideline paper, treatment/follow-up schemes in relation to OS are proposed based on serum TSH and the presence of TAI (16).…”

“…For the time being, it is suggested that euthyroid women with TAI undergoing IVF/ICSI are not being treated systematically with LT4 (16).…”

“…The increased public awareness of infertility and treatment options including ART have led to an increased use of ART world-wide, although in 2005, still 70% of ART cycles were performed in Europe and North America (39). Taken into account that guidelines from endocrine (thyroid) societies recommend the systematic screening for thyroid disorders in women of infertile couples, the detection rate/ prevalence of infertile women with a concomitant thyroid disorder increased over the years (15,16,40).…”