OBJECTIVE: To further evaluate the relationship between thyroid antibodies and preterm births.
METHODS: This is a prospective study of pregnancy outcome and demographic data combined with retrospective measurement of thyroperoxidase and thyroglobulin antibodies. Sera were obtained at 11–13 and 15–18 weeks of gestation from 10,062 women with singleton viable pregnancies (a subset from the First- and Second-Trimester Risk of Aneuploidy [FaSTER] trial).
RESULTS: Women with elevated levels of thyroperoxidase, thyroglobulin antibodies, or both in the first trimester have a higher rate of preterm delivery before 37 weeks of gestation than antibody-negative women (7.5% compared with 6.4%, odds ratio [OR] 1.18; 95% confidence interval [CI] 0.95–1.46). This is also the case for very preterm delivery before 32 weeks of gestation (1.2% compared with 0.7%, OR 1.70; 95% CI 0.98–2.94). Preterm premature rupture of membranes is also increased (2.0% compared with 1.2%, OR 1.67; 95% CI 1.05–2.44). These associations are less strong for second-trimester antibody measurements.
CONCLUSION: The present data do not confirm strong associations between thyroid antibody elevations and preterm birth found in three of five previously published reports. Preterm premature rupture of membranes appears to contribute to the thyroid antibody-associated early deliveries, possibly as a result of inflammation.
LEVEL OF EVIDENCE: II
Elevated thyroid antibody levels in early pregnancy are weakly associated with early delivery and preterm premature rupture of membranes.
From the Women and Infants Hospital and Alpert Medical School of Brown University, Providence, Rhode Island; the Savjani Institute for Health Research, Standish, Maine; Columbia University College of Physicians and Surgeons, New York, New York; the Royal College of Surgeons in Ireland, Dublin, Ireland; the University of Utah and Intermountain HealthCare, Salt Lake City, Utah; the Swedish Medical Center, Seattle, Washington; and Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, New York.
Partially supported by grant RO1 HD 38652 from the National Institutes of Health and the National Institute of Child Health and Human Development.
Corresponding author: James E. Haddow, MD, Co-Director, Division of Medical Screening & Special Testing, Women and Infants Hospital, Alpert Medical School of Brown University, 70 Elm Street, 2nd Floor, Providence, RI 02903;e-mail: email@example.com.
Financial Disclosure Geralyn Lambert-Messerlian is a consultant to Beckman Coulter, Inc. The other authors did not report any potential conflicts of interest.