Thyroid testing and management of hypothyroidism during pregnancy: a population-based study.

Abstract

There are international guidelines on thyroid function testing and management of hypothyroidism during pregnancy. Few studies have evaluated how they are implemented into clinical practice. In this descriptive study, we assessed the implementation of international guidelines in this field into local guidelines and also into clinical practice. In a nationwide survey, all guidelines in Sweden were collected (n = 29), and the adherence of the local guidelines to The Endocrine Society Guidelines 2007 was evaluated. In a follow-up in 1 district, 5254 pregnant women with an estimated date of delivery between January 1, 2009, and December 31, 2011, were included for subsequent review of their medical reports. All but 1 district had guidelines on the subject. All local guidelines included fewer than the 10 listed reasons for thyroid testing recommended by The Endocrine Society Guidelines. Furthermore, most guidelines recommended additional types of thyroid function tests to TSH sampling and lower trimester-specific TSH upper reference limits for women on levothyroxine treatment (P < .001). In the follow-up, the thyroid testing rate was 20%, with an overall frequency of women with trimester-specific elevated TSH of 18.5%. More than half of the women (50.9%) who were on levothyroxine treatment at conception had an elevated TSH level at thyroid testing according to The Endocrine Society Guidelines. The local guidelines are variable and poorly compliant with international guidelines. Performance of thyroid testing is not optimal, and rates of elevated TSH at testing are extremely high in subgroups.