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Investigating the association of volatile organic chemicals with preterm birth in Detroit, Michigan: The Center for Leadership in Environmental Awareness and Research (CLEAR) birth cohort protocol
ABSTRACT
Background:
Preterm birth (PTB), or birth before 37 weeks gestation, remains a significant public health issue in the United States, particularly in Detroit, Michigan. Growing evidence suggests that volatile organic compounds (VOCs), aromatic or chlorinated organic compounds that vaporize readily, may influence PTB risk. However, much of this prior work is limited by indirect VOC exposure estimates (e.g., assignment based on maternal residential address), with single point or cumulative exposure estimates in pregnancy, or with limited consideration of potential mechanistic factors. The Center for Leadership in Environmental Awareness and Research (CLEAR) birth cohort has been designed to evaluate the association between VOC exposure across pregnancy and PTB. CLEAR is unique in that it will directly assess VOC levels (metabolites) in maternal urine and will also examine maternal inflammation and placental changes that may be associated with exposure to VOCs.
Objective:
To describe the justification and protocol for the ongoing CLEAR birth cohort.
Methods:
A prospective cohort of ~1075 pregnant patients being seen for prenatal care at Henry Ford Health will be recruited. Pregnant patients residing in Detroit or receiving prenatal care at a Detroit-based Henry Ford Health women’s health clinic are eligible. Pregnant patients are followed until delivery. Up to 3 urine and blood samples (at early, mid and late pregnancy) are obtained for measurement of VOC metabolites and inflammatory biomarkers, respectively. The placenta is obtained after delivery for epigenomic and transcriptomic measurement. Surveys are sent to pregnant participants to assess a variety of lifestyle, psychosocial, medical, residential, and other factors. The electronic medical record is used to obtain additional medical and delivery data, including infant sex and date of delivery/gestational age at delivery. Address information collected (from both surveys and electronic medical records) across pregnancy will be used to identify potential sources of VOC exposure. A nested case-control approach (frequency matching PTB cases 1:1 to full-term controls based on infant sex and maternal race) will be applied.
Results:
Recruitment began in November 2023. Through 10/27/2025, 394 pregnant patients have consented to participate in the CLEAR birth cohort.
Conclusions:
The CLEAR cohort will provide novel data on the role of VOCs, over pregnancy, on the risk of PTB. Additionally, the role of VOC exposures over pregnancy on maternal inflammation and placental function will be examined. Finally, potential sources of VOC exposures, which could be targets for environmental remediation, will be identified.
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Copyright
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