Child of a mother with Autoimmune Hypothyroidism: frequently asked questions
Article written by our Pediatric Endocrinologist Dra. Laura Alonso Gamo
One of the most common endocrinological problems in pregnant women, along with gestational diabetes, is autoimmune hypothyroidism (Hashimoto’s thyroiditis), as it is the most prevalent endocrinological pathology in women of childbearing age. It is an autoimmune disease in which the body produces anti-thyroid antibodies: anti-thyroglobulin (anti-TG) and anti-peroxidase (anti-TPO) that hinder the function of the thyroid gland in the production of thyroid hormone. These antibodies cross the placental barrier easily, reaching the foetal blood in 95% of cases. Although long-term thyroid function in the newborn is not usually compromised, transient thyroid hypofunction is common during the first months of life.
Hypothyroidism can lead to:
– In the mother: hypertension, pre-eclampsia, anaemia, placental abruption, etc.
– In the foetus: prematurity, respiratory distress or low birth weight, congenital malformations…
I have hypothyroidism and I am pregnant, what should I do?
Ideally, you should plan your pregnancy, but if you have not done so, it is recommended that as soon as you know you are pregnant (positive test) you make an appointment with your gynaecologist or endocrinologist so that they can increase the dose of thyroid hormone compared to the dose you were taking previously. This is because this hormone is essential for the baby’s brain development.
How should I take the medication?
It is advisable to take thyroid hormone on an empty stomach and, if you are also taking oral iron, to take it separately.
What else should I do?
Iodine is necessary for the production of thyroid hormones. Every woman of childbearing age should consume iodised table salt. If she does not, she should ideally start taking iodised table salt at least 4-5 months before becoming pregnant.
In subsequent check-ups with my endocrinologist, my TSH has shot up compared to what it was before I was pregnant and they keep increasing the dose of thyroid hormone, should I be worried?
Don’t worry, it is normal for Hashimoto’s thyroiditis to get out of control during pregnancy and in some patients it is necessary to increase the dose of thyroid hormone in subsequent check-ups during the rest of the pregnancy. Normally, after giving birth, you can return to the dose you were taking before.
And now that my baby has been born, do I have to do any check-ups?
In Spain, all babies are given the famous heel prick or endocrine-metabolic screening test at around 48 hours of age. This test includes the determination of TSH (thyroid stimulating hormone), which is a neonatal screening for congenital hypothyroidism.
There are two possibilities:
1. The TSH result in the heel prick test is normal: this does not exclude the possibility of the baby developing hypothyroidism in the first weeks of life, which is why it is recommended that an assessment be made at the paediatric endocrinology clinic so that the doctor can order a control analysis of TSH, thyroid hormones and anti-thyroid antibodies between the second and fourth week of life. Subsequently, depending on the results, you will be told whether further tests or even treatment is necessary. In many cases the antibodies are elevated (which have passed through the placenta) but without compromising thyroid function, so that only serial analyses will be required until these antibodies are negative. This can take up to 6 months.
2. The TSH result in the heel prick test is elevated: you will be called to confirm the result and the blood test will also be extended with thyroid hormone and anti-thyroid antibodies. Depending on the definitive results, they will indicate whether or not it is necessary to treat the baby.
If you have any doubts, do not hesitate to contact us, we have Paediatric Endocrinology consultations available at your home.
