Date of Award


Document Type

Open Access Thesis


Epidemiology and Biostatistics


The Norman J. Arnold School of Public Health

First Advisor

Nansi Boghossian


Objective: The objective of this thesis is to investigate the effects of maternal thyroid dysfunction on maternal pregnancy outcomes.

Setting and Participants: The NICHD Consecutive Pregnancy data set contains information on a total of 114,679 pregnancies from 51,086 women who delivered ≥ 20 weeks of gestation. The data come from 20 different hospitals throughout the state of Utah and were collected between the years of 2002 to 2010.

Main Outcomes: Main outcomes of interest included: breech presentation, chorioamnionitis, gestational diabetes, gestational hypertension, hemorrhage, inductions, placental abruption, placental previa, preterm birth, premature rupture of membranes (PROM), preeclampsia, and superimposed preeclampsia.

Methods: Results are presented as RRs with 95% CIs. RRs are obtained from modified Poisson regression models. Analyses are to singleton pregnancies. All results are adjusted for insurance, parity, race/ethnicity, age, smoking, and other chronic diseases.

Results: We found that hypothyroidism is significantly associated with gestational diabetes [RR: 1.28, 95% CI: 1.00-1.63], gestational hypertension [RR: 1.32, 95% CI: 1.07- 1.63], inductions [RR: 0.98, 95%CI: 0.96-0.99] and preterm birth [RR: 1.23, 95% CI: 1.08-1.41] after adjusting for confounders. Hyperthyroidism was found to be significantly associated with gestational diabetes [RR: 2.47, 95% CI: 1.28-4.76], preterm birth [RR: 2.31, 95% CI: 1.61-3.32], and preeclampsia [RR: 2.65, 95% CI: 1.44-4.87] after adjusting for confounders. Unspecified thyroid disorders were significantly associated with gestational hypertension [RR: 1.24, 95% CI: 1.01-1.53], placental abruption [RR: 1.29, 95% CI: 1.01-1.64], and preterm birth [RR: 1.20, 95% CI: 1.05-1.37] after adjusting for confounders. Adjusted results for other thyroid disorders were not significant.

Conclusions: The results of this study suggest that the presence of a thyroid disorder increases the risk of adverse outcomes during pregnancy. This supports previous findings but more research involving large racially diverse cohorts with available data on treatment is needed to further understand the complex association between thyroid disorders and pregnancy outcomes.


© 2016, Brittany Sullivan

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