Undergraduate Honors Theses

Thesis Defended

Winter 2015

Document Type


Type of Thesis

Departmental Honors


Integrative Physiology

First Advisor

Teresa Foley

Second Advisor

David Sherwood

Third Advisor

Matthew McQueen

Fourth Advisor

Barbara Demmig-Adams


Thyroid disorders are common endocrine disorders in the United States, affecting women more often than men. Due to the higher incidence of thyroid dysfunction in women, recent studies have been conducted to determine whether hypothyroidism could play a role in pregnancy complications. While studies have shown that clinical hypothyroidism can pose a threat to both the mother and child, fewer studies have investigated subclinical hypothyroidism. Therefore the aim of this systematic review was to determine the associations between subclinical hypothyroidism, in relation to increased thyroid stimulating hormone levels and normal tetraiodothyronine levels in pregnancy complications. The complications that were analyzed included placental abruption, premature delivery, low birth weight, intrauterine growth restriction, fetal and neonatal demise, and fetal distress. Odds ratios and relative risk ratios were collected from 11 independent studies and analyzed using a meta-analysis. A summary estimate was calculated for each complication and the results were plotted on forest plots. Of the six complications measured, intrauterine growth restriction, placental abruption, fetal distress and fetal/neonatal demise were found to be associated with subclinical hypothyroidism. Further research is suggested in order to determine: 1) whether other pregnancy complications, in addition to those researched in this study, may be related to subclinical hypothyroidism, and 2) how subclinical hypothyroidism compares to overt (clinical) hypothyroidism in terms of these pregnancy complications.