Thyroid gland in pregnancy and after childbirth

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The thyroid is a strategic organ to maintain the correct metabolism of the whole organism, a sort of "gasoline" that makes our "machine" work at its best. During pregnancy the thyroid is put through extra work, essential for the brain and somatic development of the fetus: this is why it is important to check its correct functionality and take the right amount of iodine thanks to nutrition. We talk about it with Dr. Francesco Vitale, endocrinologist, gynecologist and Director of the Women's Health Center of the city.

In this article

  • what is the thyroid
  • thyroid function
  • how to ensure proper thyroid function
  • the exams to do
  • thyroid dysfunction and pregnancy
  • the thyroid after childbirth

What is the thyroid and what is its function

The thyroid is one small gland in the shape of a butterfly located at the base of the neck, just above the collarbone. Despite its small size, the thyroid performs several functions that are essential for health. Thyroid hormones control metabolic activities, growth, development and are responsible for the functioning of many of our cells. In addition, the thyroid regulates cardiovascular function as well it also affects fertility, so much so that according to a recent study, it would be advisable to perform an evaluation of the thyroid function in all women who seek medical advice for infertility.

Read also: Female infertility, when the problem is the thyroid

Why is thyroid function important in pregnancy?

"In the first months of pregnancy the thyroid function serves the development of the central nervous system and the somatic development of the fetus - explains Dr. Vital - very important aspects for the baby's life. "For this reason, during gestation the thyroid is subjected to extra work, especially in the first trimester, when the embryo does not yet produce thyroid hormones and a maternal deficiency could have repercussions on brain development. and on fetal growth.

How can the correct function of the thyroid gland be guaranteed in pregnancy?

To ensure proper thyroid function it is important to increase the intake of iodine, an element used by our body to synthesize thyroid hormones. The iodine it can only be taken through food and in general our foods contain little of it, which is why we recommend replacing normal table salt with iodized salt. 

The Del Paesena Society of Human Nutrition recommends the introduction of 200 μg / day of iodine. "To get enough, it is important that women follow a varied and balanced diet and that they use iodized salt exclusively", explains Dr. Vital. In this way you avoid running into a deficiency and therefore having to take a supplement.

As noted in the American Thyroid Association Guidelines, iodine deficiency during pregnancy can be associated with:

  • neonatal hypothyroidism, especially for preterm births;
  • risk of miscarriage;
  • increased prenatal mortality;
  • neurodevelopmental disorders;
  • risk of congenital anomalies.

"To avoid problems of this type it is therefore very important to evaluate the functionality of the thyroid gland even before the onset of pregnancy and then check its correct functioning even during the nine months" states Vitale.

Read also: Iodized salt in pregnancy

The exams to do

Alterations of the thyroid gland are detected with a simple TSH examination, that is, the hormone that controls the regular functioning of the gland. Fortunately, nowadays the TSH dosage is inserted more and more often among the preconceptional screening tests even for women without apparent thyroid dysfunction. In fact, it is not uncommon for a woman with mild hypothyroidism (i.e. when the thyroid is poorly functioning) does not have any symptoms and for this reason it is even more important. immediately evaluate the functionality of the thyroid gland, thus allowing future mothers to intervene immediately in case of alterations.

Also read: Thyroid tests before getting pregnant

On the other hand, how do you rule if the woman suffered from a thyroid disease before pregnancy?

In women with already known hyperthyroidism or hypothyroidism, it is good to verify that the treatments in place adequately compensate the function of the organ without potential negative repercussions on the mother or the unborn child.

Those suffering from a thyroid disease can easily become pregnant, but even before conception, they will have to contact their referral endocrinologist who, depending on the disease, will advise therapies to ensure proper thyroid function for all nine months. "Fortunately, today there are drugs that can be taken even during pregnancy in total safety, without adverse effects for the mother and her baby" Vitale points out.


Hypothyroidism is a pathology that slows down the functioning of the thyroid gland due to a low presence of thyroid hormones. "This is a condition that should not be underestimated - explains Dr. Vitale - because if left untreated it can lead to a greater risk of spontaneous abortion (poly-abortion), anxiety, depression, heart problems and even a slowdown in mental functions". 

More precisely, according to the Del Paesena Society of Endocrinology, hypothyroidism is a condition associated with an increased risk of:

  • miscarriage;
  • preterm birth;
  • low birth weight;
  • stress and fetal death;
  • maternal hypertension;
  • postpartum hemorrhage;
  • anemia materna.

Furthermore, untreated hypothyroidism during pregnancy can potentially be very dangerous not only for the woman, but also and especially for her baby who could manifest delays in brain growth and development.

The woman suffering from hypothyroidism will therefore have to continue the treatment already started before pregnancy, following the new dosages that her doctor will prescribe and undergo checks of thyroid values ​​every 6-8 weeks, especially in the first trimester, to adjust the therapy.

Read also: Congenital hypothyroidism: symptoms, causes and treatments


In the case of hyperthyroidism, on the other hand, the thyroid gland functions more than normal and this could cause uterine contractions that affect the progress of the gestation itself. According to the guidelines of the Del Paesena Society of Gynecology and Obstetrics, untreated hyperthyroidism in pregnancy could result in the woman:

  • hypertension in pregnancy;
  • preeclampsia,
  • placental abruption; 
  • miscarriage;
  • premature birth;
  • heart failure; 
  • anemia.

I risks for the child they are instead:

  • low birth weight for gestational age;
  • prematurity;
  • neonatal death;
  • birth of a dead fetus;
  • congenital malformations;
  • fetal and neonatal hyperthyroidism.

In case of hyperthyroidism during pregnancy, antithyroid drugs should therefore be taken which inhibit the activity of the thyroid gland. Not infrequently, however, women with hyperthyroidism can have a remission of the disease during pregnancy, which may not require the use of drugs. 

Read also: Hyperthyroidism in pregnancy

Is it true that changes in thyroid function can occur after pregnancy?

In women with a form of thyroid disease, autoimmune thyroiditis, the immune system may reactivate after childbirth with transient forms of hypothyroidism or hyperthyroidism, which in most cases tend to spontaneous remission within 6-8 months. In this period of time, however, it is important to make the diagnosis and appropriate treatment, because alterations in the thyroid function can cause disorders to the new mother such as tachycardia, fatigue, anxiety, mood swings and depression that would prevent her from living the first months with the baby. with due serenity. "The correct functionality of the thyroid gland must not be evaluated only before and during pregnancy, but also after it, and it is important that all women are aware of it" specifies Dr. Vital

Therapies to correct hypothyroidism or hyperthyroidism (in the appropriate dosages) are compatible with breastfeeding, so the mother can continue to breastfeed. As a general rule, it is important that the mother takes the drug in divided doses and that the thyroid status of the newborn is checked periodically.

Read also: Medicines While Breastfeeding, 10 Things to Know

Sources used:

  • Advice from dr. Francesco Vitale, endocrinologist and gynecologist;
  • American Thyroid Association Guidelines, 2022;
  • Del Paesena Society of Gynecology and Obstetrics, Thyroid and Pregnancy, National reference guidelines;
  • Del Paesena Society of Endocrinology, Hypothyroidism and Pregnancy;
  • Higher Institute of Health, Thyroid diseases

  • hypothyroidism
  • pregnant and thyroid
  • pregnancy thyroid
  • thyroid disorders
  • iodized salt in pregnancy
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