Low TSH values in pregnancy. The endocrinologist answers
Hi Dr. Isabella. I wish I had some comfort. I’m 12 weeks pregnant, I did the tests and it turned out that I suffer from hyperthyroidism . My values are: TSH 0.01 (0.35-5.5) FT4 3.58 (0.89-1.76) FT3 15.6 (2.3-4.2). My endocrinologist gave me a drug called ******, I live in Spain, I don’t know if it’s also available in Italy.She told me that it can cause malformations in the baby even if the probability is very low. She didn’t say anything reassuring to me, I didn’t like the way she spoke to me. I discovered hyperthyroidism when I was three months pregnant: could it have caused harm to the fetus? Is there a drug that doesn’t hurt the baby? I thank you immensely.
Dear Mrs,
the active principle prescribed by the endorinologist (Tiamazole) is not on the market in Italy where instead we use Methimazole. However the drugs are a lot
for which I believe that the prescription that has been made to you is correct and above all necessary. The child is certainly more harmed by hyperthyroidism than by small doses of the drug.
In Italy in the first three months we prescribe another drug called Propylthiouracil. It is not available in our country so we import it from the American pharmaceutical company Abbott.
The PTU does not appear to produce fetal malformations. In my experience none of the patients I have prescribed it to have had problems with the baby afterwards.
After the first three months instead we switch to Methimazole because by now the baby has formed all the organs and this drug is less toxic on the mother’s liver. This is the optimal combination.
She is right on the third month mark where she should only take propylthiouracil for two weeks and I don’t think it’s worth it. The chances of malformations are now very low.
So my advice is this, follow the treatment prescribed for your well-being and that of the child, but change an endocrinologist since he does not trust you.
I cannot guarantee that the baby has not “suffered” from his hyperthyroidism (hormones pass the placenta) but once treated he will make a full recovery. I wish you all the best and remain available for any clarification.
Best regards
Dr. Isabella Negro
Hello doctor, I’m 36 and I’m in the 11th week of pregnancy. By doing the tests recommended by the gynecologist, the ft3 and ft4 values result in the. normally, while the tsh is 0.32. should I be concerned about my baby? In the family my mother had thyroid problems, Thanks for your attention.
Dear Mrs,
it is normal to have such a low TSH during the first three months of pregnancy (no harm to the baby), it can even go as low as 0.1. It is an effect caused by high levels of beta HCG. TSH returns to normal from the fourth month onwards. My advice, also given the familiarity with thyroid disease, is to check the TSH again in a month to confirm what I told you. It is always best to be careful during pregnancy.
Kathryn Barlow is an OB/GYN doctor, which is the medical specialty that deals with the care of women's reproductive health, including pregnancy and childbirth.
Obstetricians provide care to women during pregnancy, labor, and delivery, while gynecologists focus on the health of the female reproductive system, including the ovaries, uterus, vagina, and breasts. OB/GYN doctors are trained to provide medical and surgical care for a wide range of conditions related to women's reproductive health.