title: What is a normal thyroid-stimulating hormone (TSH) level? Effects of stricter TSH thresholds on pregnancy outcomes after in vitro fertilization.
abstract: Using a thyroid-stimulating hormone (TSH) cutoff of 2.5 mIU/L or 4.5 mIU/L, no differences in the rates of clinical pregnancy, delivery, or miscarriage were observed in this large, retrospective cohort study of first-cycle IVF patients from 2005 through 2008, after controlling for age. Although lowering the TSH threshold to 2.5 mIU/L would result in a nearly fivefold increase in the number of women being classified as hypothyroid, the lack of differences in maternal clinical outcomes must be considered in the current controversy regarding the relative merits of lowering the upper limit of normal of TSH.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, New York University Fertility Center, New York, New York, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Reh
authors.forename: James
authors.initials: J
authors.lastname: Grifo
authors.forename: Ann
authors.initials: A
authors.lastname: Danoff
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D003409:Congenital Hypothyroidism / Q000453:epidemiology; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000150:complications / Q000453:epidemiology; D007247:Infertility, Female / Q000097:blood / Q000150:complications / Q000628:therapy; D011247:Pregnancy / Q000097:blood*; D011248:Pregnancy Complications / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D011256:Pregnancy Outcome; D012016:Reference Values; D012189:Retrospective Studies; D013972:Thyrotropin / Q000097:blood / Q000502:physiology / Q000592:standards*
chemical_list: D013972:Thyrotropin