Document Type : Review Article
Authors
1
Ph.D student of Reproductive Health, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
2
Professor, Department of Obstetrics and Gynecology, Reproductive Endocrinology Research Center, Research Institute of Endocrinology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
3
Associate professor, Department of Reproductive and Midwifery, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
4
Professor, Department of Endocrine and metabolism, Research Institute of Endocrinology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Abstract
Introduction: Hypothyroidism is considered as the most common thyroid disorder during pregnancy and about 2-3% of pregnant women suffer from this disorder. Furthermore, 10-20% of all pregnant women are positive for TPO antibodies and euthyroidism. Some studies have indicated that these slight thyroid dysfunctions could also be related to poor maternal and fetal outcomes. This study was performed with the aim to increase awareness and provide a review on adverse effect of hypothyroidism on pregnancy outcomes.
Methods: In this review and prospective study, databases of Medline, Embase and the Cochrane Library were searched with appropriate keywords for relevant English manuscript. In this study, variety of studies including randomized clinical trials, cohort (prospective and retrospective), case-control and case reports that were about thyroid dysfunctions and their adverse outcome in pregnancy were used.
Among 3480 articles foumd from the electronic searches in the beginning of the study, there were 400 related articles that 130 studies were related to overt hypothyroidism, 203 related to subclinical hypothyroidism and 67 related to thyroid safety. Of these articles, 47 cases were in line with the objectives of the study that included 22 studies about hypothyroidism and 26 about thyroid safety.
Results: Overt hypothyroidism has several adverse effects on pregnancy outcomes, but there is debate on short and long term effect of subclinical hypothyroidism, and thyroid antibody positivity. Also, there is no consensus on feto-maternal complication of pregnant women with normal function of thyroid and TPO antibody positive.
Conclusions: Although the impact of autoimmune thyroid disease on pregnancy outcomes is generally accepted, however the effect of subclinical hypothyroidism without increasing TPOAb on pregnancy outcomes is controversial. Further studies on maternal and neonatal outcomes in mother's subclinical thyroid dysfunction are needed.
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