Can hypothyroidism cause miscarriage?

Hypothyroidism refers to a decrease in the secretion of thyroid hormones, which has a great impact on the fetal neurological development. I hope that expectant mothers should pay attention to this and eat more foods to promote the secretion of the thyroid gland. The symptom of hypothyroidism will not lead to fetal arrest, which means that the fetus has died. Hypothyroidism affects the fetal neurological development, but patients also need to treat hypothyroidism in a timely manner.

Thyroxine is very important for fetal development, especially fetal neurodevelopment. Especially in the early stages of pregnancy, hypothyroidism can cause fetal arrest in about 60% of pregnant women, the so-called recurrent miscarriage. Even if the pregnancy is not stopped by luck, there are still risks of premature birth, low birth weight, pregnancy-induced hypertension, fetal death, and mental retardation. Pregnant mothers must pay attention to this!

1What is hypothyroidism?

The full name of hypothyroidism is hypothyroidism, which means that the thyroid gland cannot produce enough thyroid hormone to meet the normal needs of the human body due to various reasons. It is generally more common in women than in men, and the incidence rate increases with age. If the function is impaired in a fetus or newborn, it is called cretinism; if it occurs in prepubertal children, it is called juvenile hypothyroidism; if it occurs in adults, it is called adult hypothyroidism. In severe cases, it can cause myxedema, and in more serious cases, it can cause myxedema coma.

2How to treat hypothyroidism? What are the precautions for pregnant mothers to treat hypothyroidism?

For the treatment of all patients with hypothyroidism: The general principle is to use replacement therapy for the treatment of hypothyroidism. The amount of replacement needs to be individualized according to the degree of hypothyroidism and the patient's own condition. Mild hypothyroidism generally does not require special treatment. Diet therapy can be used, such as eating appropriate amounts of seafood and supplementing iodine, the raw material for producing thyroid hormone, to achieve the purpose of treatment (this is suitable for patients with low antibodies). However, moderate and severe hypothyroidism must be treated with thyroid hormone replacement therapy. Of course, the specific dosage varies from person to person. Young patients should have their thyroid function checked regularly and adjust medication based on the indicators. It is generally recommended to control sTSH to below 2.5IU/ml, with an optimal range of 1-2.

Precautions during pregnancy: Patients with hypothyroidism who have not received isotope treatment within six months can become pregnant after their thyroid function returns to normal. Pregnant mothers need to monitor their thyroid function every month and adjust medication dosage in a timely manner to ensure the safety of the fetus and mother.

The most important thyroid function is Ft4 (serum free thyroxine), because only Ft4 can cross the placenta and supply the needs of fetal development. Ft3 (serum free triiodothyronine) and TSH cannot pass through the placenta, so they are only corrective indicators. The requirement for pregnant mother's Ft4 is to adjust it to the normal midline or above to ensure that the fetus has sufficient Ft4 for development, which requires TSH to be lower than 2.5. Especially the first three months of pregnancy is a critical period for the development of the fetal nervous system. Since Ft4 is 0.02% of total T4, the measurement error is large and needs to be corrected by TSH. As long as one of Ft4 and Ft3 is elevated, TSH will be low; if TSH is high, it means that neither Ft3/Ft4 is high, although the Ft4 measurement value may be within the normal range.

The thyroid hormone replacement during pregnancy must be pure T4 (such as Euthyrox-L-T4). Thyroid tablets are not recommended because thyroid tablets are made of dried and ground animal thyroid glands, which contain both T4 and T3. If T3 is supplemented too much, TSH will decrease, covering up the phenomenon of Ft4 deficiency. In addition, during pregnancy, total T3 and total T4 will increase because TBG (thyroid binding globulin) will increase during pregnancy. Total T4 during pregnancy is 1.5-2 times that of non-pregnant women.

After 6-7 months of pregnancy, as the fetus grows, the amount of Ft4 required gradually increases. At this time, the amount of Euthyrox (L-T4) supplemented should also be gradually increased to ensure that TSH is below 2.5. Therefore, you must check your thyroid function every month.