The impact of pregnancy on thyroid function does not end with gestation. Even after childbirth, in fact, the activity of the gland may alter. In this case we speak of post-partum thyroiditis, a form of thyroiditis that may affect women in the first months after childbirth, and it is often transient. We talk about this topic with Professor Andrea Lania, Professor of Endocrinology at Humanitas University and Head of the Operating Unit of Endocrinology at Humanitas.
The immune system against the thyroid
Postnatal thyroiditis has a frequency of around 5-7% and is the result of an autoimmune reaction to the thyroid: the immune system reacts against the thyroid tissue, causing these changes in thyroid function. It is a condition comparable to Hashimoto’s thyroiditis, the first cause of hypothyroidism even during pregnancy. These changes may tend to occur in the first twelve months of childbirth.
Hyper- and hypothyroidism
This condition is characterized by a trend with a triple phase: at first hyperthyroidism is manifested, with an increase in levels of circulating thyroid hormone, while in a second phase the woman can experience hypothyroidism and, in a third phase, thyroid function can normalize spontaneously.
Symptoms of thyroiditis post childbirth are often non-specific, devious, which can be confused with those of other conditions. Palpitations, fatigue and sleep disorders are some of the symptoms of the first phase, while in the second phase there may also be constipation and weight gain, in addition to the persistence of fatigue. About 20-30% of women who go through hypothyroidism in this phase maintain this condition in the following years as well. The pharmacological treatment is different for the two phases, symptomatic with the intake of beta-blockers in the first phase and hormone replacement therapy in the second.
Scientific research has also associated this autoimmune thyroid inflammation with post-partum depression. It is a mood disorder that can arise in the weeks following the birth of the new baby (especially between the sixth and twelfth week) characterized, for example, by recurrent negative thoughts, sadness, and sense of inadequacy. Therefore, in the presence of suspicion of postnatal depression, it is also advisable to investigate the endocrinological aspects of the patient.
Who is most at risk of developing post-natal thyroiditis? Women with other autoimmune diseases and women with antithyroid antibodies, the agents responsible for the autoimmune reaction against the thyroid gland. Even those who have already experienced this condition in previous pregnancies are at greater risk, as well as those who have thyroid dysfunction or have a family history of the condition.