Context: Thyroid disease during pregnancy has been associated with multiple adverse outcomes. Whether all women should be screened for thyroid disease during pregnancy is controversial.
Objective: The objective of the study was to determine whether treatment of thyroid disease during pregnancy decreases the incidence of adverse outcomes and compare the ability of universal screening vs. case finding in detecting thyroid dysfunction.
Design: Women in the first trimester were randomly assigned to the universal screening group or case-finding group. Women in both groups were stratified as high risk or low risk based on risk factors for thyroid disease. All women in the universal screening group, and high-risk women in the case-finding group, were immediately tested for free T(4), TSH, and thyroid peroxidase antibody. Low-risk women in the case-finding group had their sera tested postpartum.
Setting: The study was conducted at two ambulatory clinics of community hospitals in southern Italy.
Patients: A total of 4562 women were randomly assigned to the universal screening or case-finding group.
Intervention: Intervention included levothyroxine in women with a TSH above 2.5 mIU/liter in TPO antibody-positive women and antithyroid medication in women with a undetectable TSH and elevated free T(4).
Main outcome measure: Total number of adverse obstetrical and neonatal outcomes was measured.
Results: No significant differences were seen in adverse outcomes between the case-finding and universal screening groups. Adverse outcomes were less likely to occur among low-risk women in the screening group than those in the case-finding group.
Conclusions: Universal screening compared with case finding did not result in a decrease in adverse outcomes. Treatment of hypothyroidism or hyperthyroidism identified by screening a low-risk group was associated with a lower rate of adverse outcomes.