When a woman becomes pregnant, many changes occur in her body. One of those changes is in the levels of various hormones produced by the body.
In the case of thyroid-stimulating hormone (TSH), pregnant women typically produce a lower level than normal (0.4–4.0 milli-international units per liter). Some international guidelines recommend levels be no higher than 2.5–3. milli-international units per liter during pregnancy. When their TSH levels rise above this, they may experience subclinical hypothyroidism, or mildly underactive thyroid, which can cause a number of health problems if left untreated.
Today, Mayo Clinic researchers report that one of those results could be pregnancy loss. Researchers further suggest a course of action that could positively impact as many as 15 of every 100 pregnancies. In a study published in The BMJ, they show that treating subclinical hypothyroidism (not quite the level that would be treated in a nonpregnant woman) can reduce pregnancy loss, especially for those with TSH levels on the upper end of normal or higher.
“A recent analysis of 18 studies showed that pregnant women with untreated subclinical hypothyroidism are at higher risk for pregnancy loss, placental abruption, premature rupture of membranes, and neonatal death,” says Spyridoula Maraka, M.D., an endocrinologist and lead author of the study. “It seemed likely that treating subclinical hypothyroidism would reduce the chance of these deadly occurrences. But we know that treatment brings other risks, so we wanted to find the point at which benefits outweighed risks.”
Using the OptumLabs Data Warehouse, Dr. Maraka and her team examined the health information of 5,405 pregnant women diagnosed with subclinical hypothyroidism. Of these, 843 women, with an average pretreatment TSH concentration of 4.8 milli-international units per liter, were treated with thyroid hormone. The remaining 4,562, with an average pretreatment TSH concentration of 3.3 milli-international units per liter, were not treated.
Read more in this news release: Should hypothyroidism in pregnancy be treated?
MEDIA CONTACT: Sharon Theimer, Mayo Clinic Public Affairs, 507-284-5005, email@example.com