Though my friend developed gestational diabetes when she was pregnant with her first, thankfully she wasn’t one of the women who develop preeclampsia as well. Preeclampsia can develop by itself, but it can also develop from other fairly common pregnancy complications. It can also cause other types of medical complications as well, like a reduced thyroid function.

A study conducted by the National Institutes of Health found that women who suffer from preeclampsia during pregnancy are much more likely to have reduced thyroid function during the last few weeks of their pregnancy and even over 20 years after giving birth. Reduced thyroid function can cause women to become weak, fatigued, and more vulnerable to cardiovascular disease.

Dr. Susan B. Shurin, the acting director of the National Institute of Child Health and Human Development (NICHD) said that "The findings suggest that the possible development of hypothyroidism is a consideration in patients with a history of preeclampsia,” and that "reduced thyroid functioning is easy to diagnose when suspected, and inexpensive to treat. Replacement therapy substantially improves the quality of life of affected persons."

This is good news for women who are genetically predisposed to preeclampsia since it means that the risk of hypothyroidism doesn’t have to negatively impact the rest of their life. Women who know they have a history of preeclampsia or are genetically predisposed should inform their doctors soon after discovering they are pregnant. Common symptoms include high blood pressure and protein in the urine. These symptoms, however, can get more severe as pregnancy progresses and women could be at risk of dangerously high blood pressure and convulsions. The more severe symptoms can potentially be fatal and the only cure is giving birth.

Preeclampsia is thought to affect the thyroid gland at the front of the throat because its primary functions are to help control blood pressure, heart rate, and body temperature. The causes of preeclampsia are not known to doctors, though there are many sound theories. Preeclampsia and reduced thyroid functioning were linked together when it was discovered that the thyroid stimulating hormone (TSH) was elevated in pregnant women with preeclampsia. An elevated TSH count implies that the thyroid gland is not functioning properly.

Doctors recommend that women feeling the effects of a reduced thyroid during pregnancy contact their doctors right away. This goes the same for women who know they are at risk of preeclampsia or other pregnancy or medical complications such as gestational diabetes, autoimmune diseases like lupus, being heavily overweight, or carrying multiples.

Source: Study finds the link between preeclampsia and reduced thyroid function. National Institutes of Health (NIH). 2009, November 17.