Impact of Preconception and Perinatal Cardiometabolic Markers and Thyroid Dysfunction on Preterm Birth

Cardiometabolic and other clinical markers during pregnancy such as blood pressure and thyroid dysfunction have been associated with preterm birth, but less is known about the impact of preconception health factors. Research is needed to determine the effect of preconception health on preterm birth among reproductive-age women. This dissertation is comprised of three papers with the following objectives: 1) To conduct a systematic review to assess the quality and breath of current literature on preconception cardiometabolic markers and risk of preterm birth. 2) To evaluate the association between thyroid dysfunction and risk of preterm birth in reproductive-age women. 3) To determine the trajectory of blood pressure changes from the period prior to conception through pregnancy and its association with the risk of preterm birth. For Manuscript 1, we conducted a systematic review identifying articles thorough PubMed (including Medline with In-Process & Other Non-Indexed Citations), PubMed Central (PMC), Embase, and ClinicalTrials.gov. For Manuscripts 2 and 3, we used multivariable logistic regression models, generalized additive models, and/or mixed modeling. The systematic review showed considerable heterogeneity in the assessment of exposures and none of the studies assessed all cardiometabolic markers of interest. The second manuscript showed that preconception hyperthyroidism increases the risk of preterm birth, after adjusting for maternal age at conception, pre-pregnancy BMI, time between pre-pregnancy thyroid measurement and conception, education level, and hypertensive disorders of pregnancy. In the third manuscript, we showed that blood pressure trajectories change over time as a woman transitions from preconception to pregnancy to postpartum. Our systematic review highlights the need for additional studies assessing preconception measures so that future healthcare recommendations can be formulated. Our data suggest that women diagnosed with hyperthyroidism during the preconception period may have a higher risk of preterm birth in subsequent pregnancies. The period prior to conception may be a critical window to identify women at risk for preterm birth who may benefit from interventions to address abnormal thyroid function. Additionally, our data indicate that the level of change in blood pressure and rate of that change is different among women with preterm births compared to women with term births