Contents
What is the thyroid?
The thyroid is a small gland of about 20 grams, located at the base of the neck. Its shape resembles that of a butterfly with a thin central part (the isthmus), surrounded by a right lobe and a left lobe.
What is the thyroid used for?
The thyroid is somewhat the conductor of our organism. Like any gland, it secretes hormones, commonly known as T3 and T4. These act on the regulation of metabolism, that is to say on the use of energy by the body. The temperature of our body, the heart rate, but also the digestive and nervous system are under the influence of the thyroid. It also acts on the quality of the skin or hair. Our mood, our sexual desire or the regularity of our menstrual cycle are under its influence. It is thanks to iodine from the diet that thyroid hormones are made. Thyroid hormones are secreted according to our needs through the regulatory action of a hormone in the pituitary gland called TSH. The pituitary gland is a small gland located near the brain.
What role does the thyroid play during pregnancy?
Pregnancy is a period marked by changes in thyroid functioning. For the needs of the fetus, in particular its growth and the good development of its brain, the thyroid of the mother-to-be must adapt and manufacture more hormones.
To make this large amount of hormones, the thyroid requires more iodine. A lack of iodine is frequent during this period because a fraction passes by placental route in the fetus, the other part being eliminated by the kidneys in a more important way than outside the pregnancy. In some mothers, this deficiency leads to a significant increase in the thyroid, this is called goiter. Most of the time, this phenomenon is reversible. Pregnancy hormones also play a stimulating role on the thyroid gland.
Does the fetus also have a thyroid?
During the 1st trimester of pregnancy, the fetal thyroid is not yet able to manufacture its own hormones, so it is the maternal thyroid that performs this function. It is mainly involved in the maturation of the nervous system. It is only from the 4th month of intrauterine life that the baby will start to partially make its own thyroid hormones.
Hyperthyroidism during pregnancy
Sometimes the thyroid becomes racing (hyperthyroidism). This disturbance concerns about 2% of expectant mothers. Most of the time, this state is transient and disappears between the 3rd and 5th month. Some signs can alert the mother-to-be: she may have severe vomiting, lose weight, feel tired, and have a heart pounding faster than usual. This disturbance, if it persists, can lead to stunted growth of the baby or prematurity and increase the risk of toxemia of pregnancy in the mother.
Hypothyroidism during pregnancy
In other cases (0,2%), it is the opposite, the thyroid works in slow motion (hypothyroidism). The mother-to-be may have dry skin, gain too much weight, or have a heart that beats less quickly than usual. This situation can be serious for the baby who is at risk of abnormalities in psychomotor and intellectual development. Fortunately, this problem is detected systematically after birth with the Guthrie test.
Can thyroid disturbances be treated and prevented?
When the mother shows signs of thyroid dysfunction, a checkup is prescribed and treatment considered. Expectant mothers can prevent iodine deficiency by consuming certain foods – primarily seaweed, fish, shellfish, and dairy products. In France, salt is enriched with iodine, but expectant mothers should not increase its consumption. On the contrary, certain foods tend to destroy iodine: cabbages (in all their forms), radishes, mustard and cassava. Pregnant women should also stop smoking which, in addition to its known harmful effects, tends to increase the size of the thyroid. In some areas deficient in iodine, iodine supplementation may be prescribed for the expectant mother.