title: Is subclinical hypothyroidism associated with lower live birth rates in women who have experienced unexplained recurrent miscarriage?
abstract: Thyroid disorders have been associated with recurrent miscarriage. Little evidence is available on the influence of subclinical hypothyroidism on live birth rates. In this cohort study, women who had experienced miscarriage and subclinical hypothyroidism (defined as thyroid-stimulating hormone >97.5th percentile mU/l with a normal thyroxine level) were investigated; the control group included women who had experienced recurrent miscarriage and normal thyroid function. Multivariable logistic regression was used to investigate the association of subclinical hypothyroidism. Data were available for 848 women; 20 (2.4%) had subclinical hypothyroidism; 818 women (96%) had euthyroidism; and 10 (1.2%) had overt hypothyroidism. The live birth rate was 45% in women with subclinical hypothyroidism and 52% in euthyroid women (OR 0.69, 95% CI 0.28 to 1.71). The ongoing pregnancy rate was 65% versus 69% (OR 0.82, 95% CI 0.32 to 2.10) and the miscarriage rate was 35% versus 28% (OR 1.43, 95% CI 0.56 to 3.68), respectively. No differences were found when thyroid stimulating hormone 2.5 mU/l was used as cut-off level to define subclinical hypothyroidism. In women with unexplained miscarriage, no differences were found in live birth, ongoing pregnancy and miscarriage rates between women with subclinical hypothyroidism and euthyroid women.
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. Electronic address: m.m.vandijk@amc.uva.nl.
authors.forename: Myrthe M
authors.initials: MM
authors.lastname: van Dijk
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Rosa
authors.initials: R
authors.lastname: Vissenberg
authors.affiliation: Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Bisschop
authors.affiliation: Department of Obstetrics and Gynaecology, Liverpool Women's NHS Foundation Trust, Crown Street, Liverpool, United Kingdom.
authors.forename: Feroza
authors.initials: F
authors.lastname: Dawood
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Madelon
authors.initials: M
authors.lastname: van Wely
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics and Gynaecology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Mariëtte
authors.initials: M
authors.lastname: Goddijn
authors.affiliation: Department of Obstetrics and Gynaecology, Liverpool Women's NHS Foundation Trust, Crown Street, Liverpool, United Kingdom.
authors.forename: Roy G
authors.initials: RG
authors.lastname: Farquharson
mesh_terms: D000026:Abortion, Habitual / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D001723:Birth Rate; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000150:complications* / Q000175:diagnosis; D050498:Live Birth; D015999:Multivariate Analysis; D011247:Pregnancy; D018873:Pregnancy Rate; D013959:Thyroid Diseases / Q000150:complications; D013961:Thyroid Gland / Q000502:physiology; D055815:Young Adult
keywords: live birth rate; miscarriage rate; ongoing pregnancy rate; recurrent miscarriage; recurrent pregnancy loss; subclinical hypothyroidism