Isolated Maternal Hypothyroxinemia: Adverse Maternofetal Outcomes but Uncertainty About Treatment Remains.

Optimizing iodine nutrition preconception and during pregnancy would prevent a significant number of IH cases globally.[4] In addition, identifying and treating iron deficiency in gestation may also play a role in reducing IH.[19] Overall, Han et al. provide strong evidence for increased risks of multiple adverse pregnancy and neonatal outcomes in maternal IH. One major challenge in addressing IH during pregnancy is the lack of evidence for LT4 treatment benefits. Isolated hypothyroxemia (IH) is defined as a low maternal free thyroxine (fT4) level with a normal thyrotropin (TSH) concentration. Given the substantial potential for confounding in observational studies, there is currently insufficient evidence to determine whether LT4 treatment mitigates the risk of adverse outcomes during pregnancies with IH. [Extracted from the article]