Hypothyroidism is due to decreased or absent production of thyroid hormone.
Primary hypothyroidism is caused by generalized tissue resistance to thyroid hormone and disorders that affect the thyroid gland directly. It is responsible for majority of hypothyroid cases.
Central hypothyroidism is caused by hypothalamic or pituitary disorders.
In addition to the known evils of maternal smoking during pregnancy on the son’s semen quality, prenatal exposure to paternal smoking can also be harmful, according to data from the large Danish National Birth Cohort (DNBC) presented at the ESHRE 2019 Meeting.