Thyroid in pregnancy and after childbirth

Pregnancy presents a special challenge when it comes to disorders of thyroid function, since during pregnancy the need for thyroid hormones increases by 30 - 40%. Women who have a high normal level of TSH (2.5-5) and have negative antibodies or suffer from manifest or latent hypothyroidism (most often the underlying cause is Hashimoto's disease) have a higher rate of infertility, that is, it is more difficult to get pregnant! In addition, in such women, it is not possible to meet the needs for thyroid hormones during pregnancy and signs of insufficient thyroid function appear or worsen. This directly increases the risks for poor psychophysical development of the child and the course of pregnancy itself is jeopardized (spontaneous births, premature births, diabetic complications, elevated blood pressure or separation of the placenta occur more often). With reduced thyroid function, it is believed that about 20% of pregnancies will be unsuccessful, usually in the first 3 months of pregnancy.

The first trimester of pregnancy represents the most important time in which essential processes for the growth and development of the child take place and in which the proper function of the mother's thyroid gland plays an important role. However, in addition to reduced thyroid function, there are other important factors that can directly endanger pregnancy and the development of the child (genetic, immunological, hematological, etc.). Women with positive antibodies who were not treated with thyroid hormones, as well as women with positive antibodies who underwent assisted reproduction, had a higher rate of miscarriage. Therefore, it is mandatory for all women at the beginning of pregnancy to determine the level of TSH along with possibly determining the level of antibodies and the diagnostic procedure additionally includes a specialist examination and ultrasound of the thyroid gland.

In conclusion, we can state that all women with reduced thyroid function should be treated with thyroid hormones before and during pregnancy. In women who are already in the process of treatment and suffer from reduced thyroid function, the existing dose of hormone therapy should be significantly increased. The upper value of the normal level of TSH in pregnancy is 2.5. Also, all women who previously had a higher rate of pregnancy loss or are in the process of pregnancy planning or assisted reproduction, have positive antibodies and a TSH level greater than 2.5 should be treated with thyroid hormones with regular specialist examinations and determination of the TSH level. After giving birth, usually within 4-6 months, 5 - 10% of women may suffer from the so-called postpartum thyroiditis, i.e. mild inflammation of the thyroid gland. It is most likely a variant of Hashimoto's disease. Among the symptoms, complaints that indicate an increased thyroid function (hyperthyroidism) are noticed at first, then a reduced thyroid function (hypothyroidism) follows, and finally the condition normalizes (euthyroidism).

The diagnostic algorithm includes a specialist examination with ultrasound of the thyroid gland, determination of TSH and thyroid hormones and antibodies. Specific treatment is not necessary in a large number of cases, but thyroid hormones are still used in case of clinically evident hypothyroidism.