subclinical hypothyroidism and pregnancy
Last edited 08/2019 and last reviewed 06/2021
Regarding subclinical hypothyroidism in pregnancy:
- the serum TSH levels are increased above the upper limit of reference range and the free T4 values are normal (1)
- there is evidence that this condition is associated with increased risk of having a baby complicated by placental abruption, preterm birth, admission to the neonatal intensive care nursery, and respiratory distress (2)
- given its potential to reduce the miscarriage rate, T4 supplementation is recommended for infertile women with subclinical hypothyroidism and/or thyroid autoimmunity who are undergoing IVF/ICSI (3)
- seek specialist advice re: management
Reference:
- (1) Abalovich M et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2007;92(8 Suppl):S1-47.
- (2) Casey BM et al. Subclinical hypothyroidism and pregnancy outcomes. Obstet Gynecol 2005;105:239-45
- (3) Rao M et al. Effect of levothyroxine supplementation on pregnancy outcomes in women with subclinical hypothyroidism and thyroid autoimmuneity undergoing in vitro fertilization/intracytoplasmic sperm injection: an updated meta-analysis of randomized controlled trials.Reprod Biol Endocrinol. 2018 Sep 24;16(1):92