title: Combination Levothyroxine + Liothyronine Treatment in Pregnancy.
abstract: Hypothyroidism is one of the most common endocrine disorders in young women and affects 3% to 4% of all pregnancies. Inadequately treated maternal hypothyroidism is associated with numerous adverse fetal and maternal outcomes. Because of growing popularity of levothyroxine (L-T4) + liothyronine (L-T3) combination therapy for hypothyroidism in nonpregnant individuals, pregnant women are taking these medications with increasing frequency. This article reviews the theoretical dangers of combination L-T4 + L-T3 treatment during pregnancy by outlining physiological regulation of maternal and fetal thyroid homeostasis, proposed adverse fetal outcomes to combination therapy, and current recommendations on thyroid replacement in pregnancy from professional societies.
authors.affiliation: Resident-in-Training, Department of Obstetrics and Gynecology, Medical College ofWisconsin, Milwaukee,WI.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Foeller
authors.affiliation: Professor of Obstetrics and Gynecology, Chief, Division of Maternal-Fetal Medicine, and Medical Director of Labor and Delivery, Department of Obstetrics and Gynecology, University of Utah Health Sciences Center, Salt Lake City, UT.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Silver
mesh_terms: D000328:Adult; D004359:Drug Therapy, Combination / Q000009:adverse effects; D005260:Female; D005315:Fetal Diseases / Q000139:chemically induced; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D013961:Thyroid Gland / Q000187:drug effects / Q000503:physiopathology; D013974:Thyroxine / Q000008:administration & dosage / Q000009:adverse effects*; D014284:Triiodothyronine / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine