The thyroid: fertility, pregnancy, and lactation

Thyroid hormones and thyroid diseases play an important role for fertility, pregnancy, and lactation. Various guidelines and expert recommendations regarding the diagnosis and treatment of thyroid disorders in pregnancy and women who wish to conceive are partially inconsistent and often without a clear statement for or against a certain intervention, and are thus often reason for uncertainty. In this brief review we aim to summarize the current evidence on this topic with reference to patient care and we aim to translate the current literature into advice for clinical decisions in daily routine. We focus particularly on the current evidence regarding treatment of subclinical hypothyroidism in the preconception phase and in the context of infertility as well as in pregnancy, and we stress the importance of patient counseling and shared decision making regarding hyperthyroidism in the preconception phase as well as in pregnancy. We want to emphasize that several important studies were published after the release of existing guidelines on this topic, which has to be taken into account regarding current decisions for patient care. Considering that overt thyroid diseases are common in women who wish to conceive and who are pregnant, and given that they usually require adequate treatment, we recommend a general screening for thyroid dysfunction in all women who wish to become pregnant and in those with a positive pregnancy test.