Hello, my name is Brad Riva and I'm a DO PhD student at Michigan State University College of Osteopathic Medicine. I recently completed my PhD and I'm happy to share some of my work in this poster. Pregnancy related nausea is the most common symptom that pregnant women experience with upwards of 90% of women reporting some nausea during pregnancy. These symptoms can impact women's quality of life as well as her health. Typically symptoms begin early and resolve on their own. However, for many women, symptoms persist into the second and third trimester. Most pregnant women are exposed to numerous endocrine disrupting chemicals, EDCs, from consumer products such as food packaging materials and personal care products. These chemicals, which include the broad classes of phthalates and phenols, have been linked to other pregnancy specific diseases such as gestational diabetes and gestational hypertension. However, no studies have identified a link between EDCs and nausea during pregnancy. Prior studies have identified hormones as possible cause of nausea symptoms. However, results have been inconsistent and studies only investigated single hormone relationships. Thus, our objectives were to evaluate both endogenous and exogenous risk factors of persistent nausea during pregnancy. In addition, we hypothesized that the two exposures are linked and that hormones will explain the relationship between EDCs and persistent nausea during pregnancy. This has the potential to uncover additional biological underpinnings of a common pregnancy condition and to identify modifiable lifestyle factors that could decrease nausea without requiring pharmacologic interventions in pregnancy. In the secondary aim, we were interested in understanding whether fetal sex was an additional risk factor for the relationship of EDCs and hormones with nausea. In order to accomplish these objectives, we used information from the Illinois Kids Development Study, iKids. iKids is a prospective pregnancy and birth cohort run out of the University of Illinois. This cohort is relatively homogenous with mostly non-Hispanic white, higher socioeconomic, and relatively healthy women. This is the iKids prenatal timeline that shows each prenatal visit through birth. For our primary outcome of interest, nausea during pregnancy, women provided information on their symptoms at each of these indicated time points. We then used that information to classify women into four groups. Women who never had nausea, women with typical nausea, women with intermittent nausea, and our primary outcome of interest is women with persistent nausea, which we defined as nausea that ends after 17 weeks gestation. In this cohort, 25% of women had persistent nausea. For EDC exposure assessment, women provided five urine samples across pregnancy indicated by the pictures of these urine cups. Urine is the best way to approximate exposure to both phthalates and phenols because these chemicals are rapidly metabolized and excreted, and they're generally considered non-persistent chemicals. Because of their rapid excretion, the variability can be high within each person. In order to deal with that variability, we physically pooled the five urine samples, and that urine sample is used to analyze 31 phthalate and phenol urinary biomarkers. This pooling method is a validated approach to approximate across pregnancy exposure. Importantly, in iKids, most EDCs were measurable in greater than 90% of the pooled urine samples. For hormone assessment, we quantified sex steroid and thyroid hormone levels in fasting plasma samples that were collected at median 17 weeks gestation. We evaluated associations between single chemicals or hormones and nausea persistence using covariate adjusted logistic regression. One limitation of prior studies was only investigating single chemicals or single hormones rather than trying to model the actual exposure profile or the hormonal milieu. In our studies, we used quantile-based g-computation and weighted quantile-sum regression to model joint associations of EDCs with our outcomes of interest. We also used weighted quantile-sum regression to understand each hormone's contribution to nausea persistence while counting for other hormones. First, we explored the relationship of EDCs with persistent nausea in pregnancy. Each 10% increase in the EDCs was associated with a 14% higher risk of persistent nausea. In contrast, there was no relationship of EDCs with persistent nausea in women carrying females. However, in women carrying males, each 10% increase in EDCs was associated with a 26% higher risk of persistent nausea. Exploring endogenous factors, when all hormones were modeled jointly, hormones were associated with increased odds of persistent nausea in all women. There was no relationship between hormones and persistent nausea in women carrying females. However, increased hormones were associated with increased odds of persistent nausea in women carrying males. Once we established the relationship between both endogenous and exogenous factors, we wanted to understand whether they were linked. First, we explored whether EDCs disrupt hormones that are responsible for nausea. EDCs were negatively associated with testosterone and TSH, where each 10% increase in EDCs was associated with a 5.65% lower testosterone and a 0.09 unit lower TSH. Associations with progesterone, testosterone, and free T4 did not differ by fetal sex. However, in women carrying females, we identified an inverted U-shaped relationship of EDCs with estradiol, and that indicates that EDCs are associated with lower estradiol at both higher and lower levels of exposure. Additionally, in women carrying females, each 10% increase in EDCs was associated with a 1.5% higher total T4, whereas in women carrying males, EDCs were associated with a 0.18 unit lower TSH. Overall, we observed that phthalates and phenols from both food packaging materials and personal care products were associated with an increased risk of persistent nausea in all women, but primarily due to women carrying males. Unsurprisingly, EDCs were associated with various hormones in all women, women carrying females, as well as in women carrying males. Lastly, hormones were associated with increased odds of persistent nausea in all women and in women carrying males. However, we did not identify clear connections between EDCs, specific hormones, and persistent nausea. Therefore, future research is needed to investigate alternative mechanisms, including EDC-driven disruptions in other hormones, metabolic, or inflammatory pathways. Additionally, future work needs to better characterize environmental contaminant sources to possibly mitigate EDC exposure and reduce nausea symptoms. Thank you for listening to my presentation.

endocrine-disrupting chemicals

pregnancy-related nausea

hormonal levels

Illinois Kids Development Study

environmental sources