In pregnancy must take into account two factors, the thyroid of the mother and the child’s thyroid. Everyone has their own personality and requires its own attention.
Child’s Thyroid .-
Regarding the protection of the child’s thyroid during pregnancy as we have discussed in Chapter Prevention of thyroid disease, but we will make a reminder surface. In relation to the thyroid of children we must remember the “rule of three”
After three weeks of conception begins to form the outline of what should be the thyroid of children, women at this time often do not know yet who is pregnant, from the third month of conception, the fetal thyroid is already able to accumulate iodine, operate and produce their own hormones, three weeks after birth the newborn has used hormones that could come from his mother, he has exhausted their deposits and began to operate connected to the pituitary.
During pregnancy the embryo first and later fetus are highly protected. They have two possibilities of using thyroid hormones, those which he makes and those of his mother passing the placenta. If your mother has a severe hypothyroidism, the child uses the hormones that it produces, if the child has thyroid agenesis, ie a congenital lack of thyroid, also has no problem, use the hormones that supplies his mother. In both cases the child is born quite normal in their development.
The problem occurs when there is a lack of iodine to produce thyroid hormones. Under these circumstances it works well and the thyroid of the mother or the fetus, and then there are problems. Why am I so insistent with the theme of food rich in iodine and in case of doubt, which is always, use iodized salt. But that is what we discussed at length in the chapter on Prevention.
Mother’s Thyroid .- Modifications induced by pregnancy .-
Although she is a woman you absolutely normal for thyroid pregnancy is a major impact. But do not worry you are prepared for that and more. That gender equality is stupid, women are physiologically better equipped than men.
Pregnancy is accompanied by the influence of a number of factors specific to this condition which together are a major stimulus of the thyroid of the pregnant woman.
The first factor, which influences all in the first quarter, thyroid stimulating hormone produced in the placenta, chorionic gonadotropin Let’s talk a little about it. Production begins immediately with the conception, to 2 to 3 days. It is this hormone that is detected in blood or urine and is the basis of pregnancy tests. Well, chorionic gonadotropin is very similar to TSH and may stimulate the thyroid. Approximately 18% of pregnant women during the first quarter a slight stimulation of the thyroid that slips between the other pregnant women feel discomfort. There may be a slight elevation of T4 and TSH frenación the first quarter is normal and should not be confused with hyperthyroidism. In the second and third quarter levels drop box chorionic gonadotropin and tends to subside.
Well, if there is an increase of thyroid hormones in blood and inhibition of TSH, a gynecologist and endocrinologist are entitled to think there may be a situation hyperfunctional. But there are data that can help make a difference: first antibodies and normal thyroid ultrasound is mostly normal in this false hyperthyroidism might be called the first trimester of pregnancy. In hyperthyroidism there is increased real vascularity in the thyroid gland appears as a low echogenicity, the study echo-color Doppler is very apparent increased vascularity in the false hyperthyroidism is strictly normal thyroid ultrasound.
In the second and third quarter are also factors that alter thyroid function, but are otherwise. Although not entirely clear, this problem could be implicated themselves female hormones, primarily estrogen. We discussed in the opening chapters of Physiology which circulating thyroid hormones in blood mostly bound to a protein called TBG (thyroxine binding globulin globulin or Bindig or carriage of thyroxine), well in pregnancy figures TBG soar, between 16 to 20 weeks of gestation the number of blood TBG bends. In these circumstances the levels of T4 and T3 in blood are altered and can give the false impression of a functional impairment. But this issue is resolved, because the T4-Free is unchanged and remains normal. Simplify and summarize:
In pregnant by changes in hormonal status can be seen discrete alterations in the levels of T4-T3 and TSH. -Free T4 is not altered. Conventional ultrasound and echo-color doppler (vascularization), are normal.
For the reasons previously mentioned the thyroid of the mother during pregnancy is forced. It is estimated that the thyroid of the pregnant woman produces between 30% and 50% more than in normal thyroxine. To maintain the level of T4-Free stabilized blood must increase its rate of production and also the mother to fetus transfer a portion of your hormones, not much, but enough to maintain normal growth if the fetus had problems with your thyroid .
In pregnancy the mother’s thyroid can grow a little. But perhaps not always in a 10 to 15% of cases. This checked by ultrasound. But it’s a very discreet and you can later return to their normal size.
Regulation of thyroid function in pregnant women with iodine deficiency .-
Normally, as we previously indicated, the moderate exertion which requests the thyroid is fine, but if there is a deficiency in iodine the situation is different. The thyroid of the mother is insufficient to produce the hormone necessary because not enough iodine without material may not be can not build a house. The mother’s TSH is elevated and the thyroid of the mother increases. The boy has got it all and also can be born with a small goiter, apart from the problems of development that could have had. But this is explained more fully in Chapter Prevention.
The iodine requirements of a normal woman is 150 micrograms daily, the woman needs 200 micrograms. Iodine supplementation either as single dose “shock” in the first two months of pregnancy or compounds included in multivitamin and polimineral type models currently used can solve this problem.
Tags: Pregnancy, thyroid
