New research from the UK reveals that treating women with thyroid antibodies yet normal thyroid functioning, with a medicine known as Levothyroxine, will not increase their chances of delivering a baby.
“Levothyroxine treatment, started before pregnancy, in women with normal thyroid function and thyroid peroxidase antibodies who have a history of miscarriage or infertility, does not improve the chances of live birth,” said the lead author of the study, Dr. Rima Dhillon-Smith. “We were surprised because previous small studies suggested there could be a benefit with levothyroxine treatment in women with thyroid antibodies.”
The authors of the study conducted double-blind research of women with normally functioning thyroid function from age group 16-41 who had had a miscarriage or were infertile and wanted to conceive naturally or with some sort of assistance. From 2011-2016, 470 women were given 50mcg of levothyroxine daily and 470 were given a placebo. Their medication continued from before conception to the end of their pregnancy. The results in both groups were found to be similar. This means that 56.6% of the women who were given levothyroxine, and 58.3% who were given placebo got pregnant. Furthermore, 37.4% of the ones taking levothyroxine, and the 37.9% taking placebo gave live births. Some other pregnancy outcomes were also similar in both groups such as pregnancy loss as well as preterm birth. Adverse event rates were also found similar i.e. 6% of women in levothyroxine group and 4% in the C.
“Thyroid peroxidase antibodies are found in the blood in approximately one in 10 women who have normal thyroid function, and they have been linked to increased risk of miscarriage and preterm birth,” Dhillon-Smith added.
“The American Thyroid Association and other international guidelines currently recommend the consideration of levothyroxine treatment for women with thyroid antibodies, as there is thought to be minimal chance of harm and a potential to help increase the chance of having a live birth,” she also said.
“As our study was large and of high quality, we can be confident that levothyroxine does not improve pregnancy success for women with thyroid antibodies and normal thyroid function and therefore should not be recommended or used in clinical practice,” said Dhillon-Smith. “This will mean no longer providing unnecessary medication to women who do not need it.”