Importance: Hypothyroidism is one of the most prevalent diseases in pregnancy, but there is no consensus about its management in pregnant women.
Objective: In this systematic review, we evaluated the association between pregnancy complications and treated or untreated maternal hypothyroidism.
Evidence acquisition: PubMed and reference lists were searched for the Medical Subject Headings terms "pregnancy complications" and "hypothyroidism." The eligibility criteria for inclusion in the study were an original study published between 2002 and 2013. Six reviewers independently selected the studies, and 3 extracted the data. Two reviewers assessed the risk of bias and quality of the studies.
Results: Eighteen studies were included in the systematic review. The most prevalent complications associated with maternal hypothyroidism were abortion, intrauterine fetal death, preterm delivery, and preeclampsia. The pregnancy outcome depended on the treatment that was received by the patient.
Conclusions: Strong evidence indicates that maternal hypothyroidism is associated with maternal-fetal complications, but no consensus was found among the studies reviewed herein. The dose of levothyroxine that is required to maintain euthyroidism is still questioned, but studies have suggested that levothyroxine should be adjusted according to the gestational period and laboratory profile.