What is the situation of pregnancy complicated with hyperthyroidism?

Pregnancy complicated by hyperthyroidism means that the pregnant woman develops a disease such as hyperthyroidism during pregnancy. If it is not treated in time, the fetal mortality rate is very high, or it may cause malformations to the fetus. Pregnant women should regularly check their physical condition and fetal development at each stage to keep up to date with their physical health.

Hyperthyroidism during pregnancy

Pregnancy complicated by hyperthyroidism (HT) is one of the main causes of increased maternal and fetal mortality, second only to gestational diabetes. Untreated hyperthyroid pregnant women have significantly increased rates of premature birth, miscarriage, teratogenesis, low neonatal weight and neonatal mortality. According to the 2002 NHANES survey data, the prevalence of hyperthyroidism in the United States is 1% (0.4% for clinical hyperthyroidism and 0.6% for subclinical hyperthyroidism), and the most common cause is toxic diffuse goiter (Graves' disease). Graves' disease is more common in women (male:female = 1:5-10), especially women of childbearing age. Therefore, hyperthyroidism during pregnancy is not uncommon, with an incidence of approximately 0.1-0.4%. Women of childbearing age with Graves' disease are the main group of patients with hyperthyroidism during pregnancy, accounting for about 85%.

Disease hazards

Hyperthyroidism during pregnancy can cause many adverse effects on pregnant women and their offspring. The adverse effects of untreated or poorly controlled hyperthyroidism on pregnancy outcomes include: effects on pregnant women include stillbirth, premature birth, preeclampsia, congestive heart failure, thyroid crisis, miscarriage, placental abruption and infection; effects on the fetus include neonatal hyperthyroidism, intrauterine growth retardation, premature birth, and small for birth (SGA). In addition, hyperthyroidism during pregnancy can also lead to various types of thyroid dysfunction in the fetus and newborn, including fetal and neonatal hyperthyroidism or fetal and neonatal hypothyroidism. The effects of hyperthyroidism at different stages of pregnancy are also different. Hyperthyroidism in early pregnancy increases the risk of spontaneous abortion; hyperthyroidism in mid-to-late pregnancy significantly increases the risk of gestational hypertension, preeclampsia, and premature birth. In addition, pregnancy can also aggravate hyperthyroidism, leading to hyperthyroid heart disease, congestive heart failure, and even hyperthyroid crisis. Millar reported the impact of hyperthyroidism on pregnancy in 181 cases, and the incidence of SGA was 9 times that of the normal pregnancy group. Momotani reported that the incidence of fetal malformations in untreated hyperthyroid patients was 6%, while the incidence in the ATD treatment group was 1.7%, and the incidence in the group with normal thyroid function was only 0.2%.

Clinical manifestations

The clinical manifestations of hyperthyroidism in pregnant women are the same as those in non-pregnant women, both showing varying degrees of thyrotoxicosis, such as heat intolerance, sweating, palpitations, slow weight gain, and increased frequency of bowel movements. During pregnancy, normal pregnant women may also experience symptoms similar to thyrotoxicosis, such as sweating, heat intolerance, rapid heartbeat, and irritability, which are sometimes difficult to distinguish from the clinical manifestations caused by hyperthyroidism. However, during pregnancy, if the pregnant woman has slow weight gain, no weight gain or even weight loss, thyroid enlargement with vascular murmurs, increased heart rate, proximal muscle weakness, etc., especially if there is proptosis or pretibial myxedema, or a history of hyperthyroidism or autoimmune thyroid disease, or a family history of thyroid disease, she should be highly alert to the possibility of hyperthyroidism.