Pregnancy and hypothyroidism

Based on a new study of nearly 118,000 women, researchers estimated that nearly 500,000 pregnant women with gestational hypothyroidism may go undetected each year.

Asian women were almost five times more likely to test positive for gestational hypothyroidism than African-American women (19.3% compared with 6.7%) and slightly more likely than Caucasian and Hispanic women (16.4% and 15.2%, respectively).

Gestational hypothyroidism has been linked to medical complications for both mothers and babies. However, the appropriate diagnostic approach and management of the condition remains controversial. The researchers wanted to analyze the current status of testing for thyroid disease during pregnancy.

Of the pregnant women in the study, Asian women had the highest testing rate of 28% and African-American woman had the lowest rate at just 19%. Testing rates increased with maternal age.

The analysis found that women 35 to 40 years of age were 2.2 times more likely to be tested when compared than women between 18 and 24.  Weight was also a factor as those over 275 pounds  were 1.3 times more likely to be tested than those weighing between 100 and 124 pounds .

Younger women were slightly underrepresented in the study population and older women were slightly overrepresented. Given the higher rates of gestational hypothyroidism among older women, the authors suggested that the overall rate is slightly lower than what they report.

“Because national and international endocrine and obstetrical organizations may consider the implications of universal prenatal and antenatal screening, this study demonstrates that the proportion of women tested for gestational hypothyroidism is low,” wrote the authors. “(I)f outcomes are shown to improve with intervention, then this may have a significant impact on the health of a large number of women and their children.”

All three authors are employed by Quest Diagnostics.
Source reference:
Blatt AJ, et al “National status of testing for hypothyroidism during pregnancy and postpartum” J Clin Endocrinol Metab 2012; 97: DOI: 10.1210/jc.2011-2038.