What complication can arise from untreated hypothyroidism during pregnancy?

Untreated hypothyroidism during pregnancy can lead to serious complications, primarily affecting fetal development. One major concern is the risk of fetal developmental issues, including cretinism, which is a severe form of developmental delay caused by untreated congenital hypothyroidism. The thyroid hormone is crucial for the development of the fetal brain and nervous system, particularly during the first trimester when the fetus is most vulnerable.

When a pregnant individual has hypothyroidism that is not adequately managed, the lack of sufficient thyroid hormones can hinder normal fetal growth and cognitive development, potentially resulting in long-term impairments. Cretinism, characterized by severe physical and mental developmental delays, underscores the importance of proper thyroid hormone levels throughout pregnancy for the health of the fetus.

While the other options, such as insomnia, anxiety, excessive weight gain, and gestational diabetes, may be associated with various health conditions in pregnancy or related hormonal imbalances, they are not directly linked to the critical effects of untreated hypothyroidism on fetal development. Therefore, the primary and most concerning complication of untreated hypothyroidism during pregnancy is indeed the risk of fetal developmental issues and cretinism.