ABSTRACT
Thyroid pathology worsens during pregnancy. Hypothyroidism can be pre-existent or may begin during pregnancy period. Most of the patients who presented hypothyroidism during pregnancy have a history of thyroid disease for which they have undergone treatment (medical, surgical or radioisotopes). Hypothyroidism is difficult to be diagnosed during pregnancy as the signs can belong to pregnancy itself. Changes in thyroid function have a major negative impact on both mother and fetus.Complications that arise depend on the severity of hypothyroidism, on how appropriately and early the treatment will be initiated, on other obstetrical and extragenital pathologies associated with the present pregnancy. Clinical symptoms are polymorphic, often nonspecific, and are related mainly to the time of occurrence and to the severity of thyroid hormone deficiency. The appropriate, early administered treatment and maintenance of a normal level of thyroid hormones minimize the risk of maternal and fetal complications and make it possible that the pregnancy may be carried to term without severe complications.