Post-Partum Thyroid Dysfunction

Abstract

Normal pregnancy is associated with two major series of alterations in the endocrine system. On the one hand hormonal changes necessary for the maintenance of pregnancy must occur and on the other pregnancy itself may influence the function of endocrine glands, such as the thyroid, which are not themselves directly involved in the maintenance of the pregnancy. In pregnancy therefore, and as a result of these normal physiological regulatory mechanisms, thyroid function must be interpreted with caution (Table 1). The situation is further complicated in those women with known (or previously unrecognised) thyroid disease, particularly if the aetiological basis of their disease is autoimmune (Table 1). In these women pregnancy may have a profound impact on their disease with amelioration during the pregnancy itself but with exacerbation in the post-partum period. In addition and as a result of their thyroid disease, alterations in the function of the foetal and neonatal thyroid may occur. Considerable interest has been focussed recently on alterations in thyroid function in pregnancy and the post-partum period in both normal women and women with known autoimmune thyroid disease and has been extensively reviewed (1-3). In the present study we have sought to examine prospectively the thyroid function of a group of normal women with no known history of thyroid disease, through pregnancy and the post-partum period. Our aim was to define the true prevalence of post-partum thyroid dysfunction (PPTD) in such women, to characterise the syndromes of PPTD developing and to determine the factors associated with their development.