pregnancy with hypothyroidism
Introduction
Introduction to pregnancy with hypothyroidism Hypothyroidism (hypothyroidism, referred to as hypothyroidism) women often appear anovulatory menstruation, infertility, combined with less common pregnancy, the most common pregnancy with hypothyroidism is autoimmune thyroid disease - chronic lymphocytic thyroiditis. The antibody produced by the immune dysfunction of the body causes diffuse lymphocyte infiltration in the thyroid tissue, leading to goiter and hypothyroidism. basic knowledge The proportion of illness: 0.005% Susceptible population: pregnant women Mode of infection: non-infectious Complications: miscarriage premature infants
Cause
Pregnancy with hypothyroidism
(1) Causes of the disease
1. Thyroid hypothyroidism accounts for more than 90%, which is caused by thyroid disease itself.
1 inflammation: can be caused by immune response or viral infection; the cause is unknown, especially chronic lymphocytic thyroiditis, subacute thyroiditis hypothyroidism is generally temporary.
2 radiotherapy: after 131I treatment or after cervical radiation therapy.
3 thyroidectomy or subtotal resection.
4 caused by iodine deficiency: more common in endemic goiter areas, a small number of high iodine areas can also occur goiter and hypothyroidism, long-term intake of large amounts of iodine, can cause hypothyroidism, the pathogenesis of which is unknown.
5 medullary thyroid carcinoma or extensive metastatic cancer in the thyroid gland.
6 drugs: lithium, thiourea, sulfonamide, salicylic acid and other drugs can inhibit thyroxine synthesis caused by hypothyroidism.
2. hypothalamic or pituitary lesions secondary hypothyroidism hypothalamus or pituitary gland inflammation, tumor, surgery or radiation therapy, postpartum hemorrhage, causing pituitary ischemia, may be due to thyroid stimulating hormone (TRH) or thyroid stimulating hormone ( TSH) decreased secretion, resulting in T3, T4 synthesis and secretion decreased, forming hypothyroidism.
3. Patients with thyroid hormone resistance syndrome have normal secretion of pituitary and thyroid gland, and peripheral target tissue and organ receptors are defective. They are not sensitive to thyroid hormone and produce resistance. The clinical manifestations of hypothyroidism require thyroid hormone therapy.
4. Pregnancy combined with hypothyroidism is mainly seen in three cases:
1 hypothyroidism occurs in juvenile or adolescent, pregnancy after treatment.
2 hypothyroidism occurs in adulthood and is pregnant after treatment.
3 hyperthyroidism, adenoma after radiotherapy or surgery secondary hypothyroidism, after treatment and pregnancy, about 1% of hypothyroidism women can be pregnant after treatment.
(two) pathogenesis
1. The effect of pregnancy on hypothyroidism Increased blood volume caused by pregnancy, increased glomerular filtration rate and increased iodine clearance rate, all of which promote serum iodine levels, and the demand for thyroid hormones during pregnancy is greatly increased. The hypothyroidism has a serious tendency to aggravate, which is undoubtedly a stress state for the thyroid gland. The thyroid tissue is compensatory hypertrophy and can cause a goiter-like enlargement. After the first trimester, the anti-thyroid hormone antibody titer increases with pregnancy. There is a decrease, the symptoms of hypothyroidism can be improved, but rebound can occur after childbirth.
2. The effect of hypothyroidism on pregnancy
(1) Incidence of pregnancy-induced hypertension: The severity of hypertension is related to the severity of hypothyroidism. The cause may be due to decreased cardiac output, increased peripheral vascular resistance, secondary enhancement of sympathetic tone and alpha-adrenal gland. The response of the prime energy; in addition, anti-thyroid antibodies can produce immune complex deposition in the glomerulus and placenta, and are prone to pregnancy-induced hypertension.
(2) prone to miscarriage, premature delivery, limited fetal growth, fetal death, low birth weight, neonatal death, etc., hypothyroidism patients have lower basal metabolic rate, physiological activity is at a low level, plus less intake, The nutritional status is worse than that of normal pregnant women, and the intrauterine growth and development environment provided by the fetus is poor, which may cause the above-mentioned poor prognosis. In addition, premature birth due to pre-eclampsia and other complications leads to an increase in perinatal mortality (20%). .
In recent years, pregnant women have been found to have thyroid antibodies (anti-peroxidase, anti-microsome, anti-thyroid globulin). Regardless of thyroid function, the risk of miscarriage increases, and the incidence of spontaneous abortion is twice that of normal people. The toxic effects of thyroid antibodies, or whether they are only a state of autoimmune abnormality, or suggest that patients also have other antibodies (such as antiphospholipid antibodies) that cause recurrent miscarriage, have not yet reached a clear conclusion, in general, the presence of anti-thyroid antibodies Fetal and neonatal hazards have little to do with thyroid function.
(3) The effect of hypothyroidism on fetal and neonatal thyroid function: The mechanism of thyroid function in pregnant women affecting their offspring development is still unclear. In recent years, many literatures suggest that a small amount of thyroxine crosses the placenta and enters the carcass. Before the expression of thyroid function, these small amounts of hormones are much more important for the development of fetal brain marrow than in previous settings. Animal experiments have confirmed that a small amount of thyroxine that enters the carcass through the placenta is extremely important for brain development before the thyroid function begins.
In recent years, there have been reports of untreated hypothyroidism in pregnant women. The study confirmed that iodine and TRH can rapidly pass through the placenta. At 12 weeks of gestation, the fetal thyroid gland can take up iodine and synthesize thyroid hormone; after 20 weeks of gestation, the pituitary-thyroid axis is negative. The feedback mechanism has been established and is self-contained, independent of the maternal thyroid axis system; therefore, although pregnant women suffer from hypothyroidism, as long as there is enough iodine to enter the carcass through the placenta, fetal thyroid function can be completely normal.
If the fetus is seriously deficient in iodine, it can cause irreversible damage to brain development. In the future, it will develop into cretinism with mental impairment as the main feature and hypothyroidism. If the degree of iodine deficiency is mild, it will develop into subclinical cretinism. .
Prevention
Pregnancy with hypothyroidism prevention
1. Many hypothyroidism is mainly caused by autoimmune thyroiditis, iodine deficiency, radiation therapy and surgery. For example, early treatment can reduce the incidence. For example, in areas with local iodine deficiency, iodized salt is used to supplement iodine, especially pregnant women. Iodine deficiency, otherwise the incidence of congenital dysplasia increases.
2. Caused by drugs, attention should be paid to timely adjustment of dose or discontinuation.
3. Vigorously promote modern screening and diagnosis methods, early diagnosis after intrauterine or postnatal, early treatment, will significantly reduce the incidence of congenital hypothyroidism in neonates and improve their poor prognosis.
Complication
Pregnancy with complications of hypothyroidism Complications, premature birth, abortion
Pregnancy with hypothyroidism is prone to miscarriage, stillbirth, low birth weight, fetal intrauterine growth arrest.
Symptom
Pregnancy with hypothyroidism Symptoms Common symptoms Dry skin fatigue Fatigue Sleepiness Apathy edema Hair loss Hairless skin Rough nodules
Symptoms of pregnancy with hypothyroidism, the most common are fatigue, weakness, weakness, lethargy, apathy, depression, slow reaction, hair loss, dry skin, less sweating, poor appetite, weight gain, muscle Tonic pain, may cause pain and burning sensation in the fingers and hands, or abnormal symptoms of numbness, slow and weak heartbeat, lower heart sounds, a few heart palpitations, shortness of breath, low voice or hoarseness, prolonged squat reflex delay period, The signs are action, speech is slow, the skin is pale, dry, inelastic, the late skin is depressed edema, the hair is sparse and dry, dull, and the thyroid is diffuse or nodular.
Examine
Pregnancy with hypothyroidism
1. Determination of serum TSH levels
It is the best indicator for the diagnosis of hypothyroidism. It can be based on the clear diagnosis of TSH in the primary stage of primary hypothyroidism. The increase of TSH level combined with serum free thyroxine index (FT4I) and thyroid peroxidase antibody or other antibody detection; FT4I Below normal, the body's biologically active thyroid hormone is in a state of deficiency.
2. Serum T4 value
Below normal, the resin T3 uptake ratio (RT3U) is significantly reduced, and these abnormal results are often obtained before clinical symptoms appear.
3. Blood routine examination
Patients with hypothyroidism often have anemia (30% to 40%). Because of the decrease in erythrocyte production rate, they are mostly positive cell anemia. There are also megaloblastic anemia due to vitamin B12 or folate deficiency; if small cell anemia occurs Mostly caused by iron deficiency at the same time, white blood cell and platelet counts are basically normal, but occasionally due to abnormal platelet function, bleeding is likely to occur.
4. Other biochemical tests
It is often found that blood lipids and creatinine, phosphoric acid kinase concentration, liver function tests may have mild reversible abnormalities.
Diagnosis
Diagnosis and differentiation of pregnancy with hypothyroidism
diagnosis
Mild hypothyroidism is difficult to diagnose during pregnancy because the symptoms are not obvious and non-characteristic, but if the symptoms are obvious (fatigue, cold, edema, dry hair, rough skin, etc.), combined with medical history, physical signs and laboratory tests, diagnosis is not difficult.
Differential diagnosis
The diseases that need to be identified are mainly the following:
1. The clinical symptoms of hypothyroidism in the early stage of subclinical hypothyroidism are not typical. T3 and T4 are normal or slightly lower, and TSH is slightly increased. After laboratory error is excluded, hypothyroidism can be diagnosed.
2. Low T3 syndrome Some chronic wasting diseases, such as liver and renal insufficiency, clinical manifestations of patients with hypothyroidism, laboratory tests T3, T4 is low, TSH is normal, rT3 is increased or normal.
3. Others should be differentiated from anemia, unexplained edema, coronary heart disease, pericardial effusion and other diseases.
