Why is the thyroid gland worse during pregnancy?
From the first weeks of pregnancy, the body's need for thyroid hormones increases by about a third. Blood volume increases, the level of binding proteins increases, and the hormone human chorionic gonadotropin additionally stimulates the gland. A healthy thyroid gland copes with this load, and a gland with a limited reserve - for example, with autoimmune thyroiditis or after surgery - ceases to cover the need, and TSH increases. If a woman took levothyroxine before pregnancy, the dose almost always needs to be increased in the first trimester.
- Autoimmune thyroiditis is the most common cause
- Condition after removal of part or all of the thyroid gland
- After treatment with radioactive iodine
- Severe iodine deficiency in diet
- Less commonly, diseases of the pituitary gland
Symptoms that can easily be attributed to pregnancy
The difficulty is that the manifestations of hypothyroidism are similar to the usual sensations of a pregnant woman: fatigue, drowsiness, chilliness, swelling, constipation, weight gain. That is why the diagnosis is made by blood test, and not by complaints. Subclinical hypothyroidism, when TSH is elevated and free T4 is normal, often does not produce symptoms at all and is detected only during examination.
- Severe fatigue and drowsiness
- Chilliness, dry skin, brittle hair
- Swelling of the face and hands
- Constipation
- Decreased memory and concentration
- Hoarseness of voice
What are the dangers of untreated hypothyroidism?
Lack of thyroid hormones affects the course of pregnancy and the development of the child. The first trimester is of greatest importance, when the fetal nervous system is formed. With severe uncompensated hypothyroidism, the likelihood of pregnancy complications increases, so treatment begins without waiting for complaints to appear. It is important to emphasize: with the correct dose and normal TSH, these risks are reduced to normal.
- Increased risk of miscarriage
- Arterial hypertension and preeclampsia
- Anemia in mother
- Fetal growth restriction and low birth weight
- Possible impact on the neuropsychic development of the child
What tests are needed and how often?
The main indicator is TSH; free T4 is additionally determined. The norms for pregnant women differ from general laboratory norms and depend on the trimester, so the result should be assessed by a doctor, and not a calculator on the Internet. Antibodies to thyroid peroxidase help to understand the cause and assess the risk of increasing hypothyroidism. Ultrasound of the thyroid gland shows the structure and presence of nodes. After starting or changing the dose of the hormone, TSH is monitored approximately every 4-6 weeks, and the dose is reconsidered after delivery.
- TSH - basic control
- Free T4
- AT-TPO with a newly detected increase in TSH
- Ultrasound of the thyroid gland with nodes or enlargement
- Recheck every 4–6 weeks
Treatment and prevention
Treatment consists of replacement therapy with synthetic thyroid hormone. This is the same substance that the gland produces, so it does not harm the child - it is its deficiency that harms. The drug is taken in the morning on an empty stomach with water, 30–60 minutes before meals, and separately from iron and calcium supplements, which interfere with absorption. You cannot change the dose or stop the drug on your own if you feel better. Additionally, during pregnancy, a sufficient intake of iodine is recommended; the dose of the drug is determined by the doctor.
- Levothyroxine in the dose prescribed by the doctor
- Take in the morning on an empty stomach, 30–60 minutes before breakfast
- Interval of at least 4 hours with iron and calcium supplements
- Regular TSH monitoring
- Prevention of iodine deficiency as prescribed by a doctor
- Review of dose after delivery
