Year of Publication



Public Health

Degree Name

Dr. of Public Health (Dr.P.H.)

Committee Chair

Wayne Sanderson, PhD

Committee Member

Steve Browning, PhD

Committee Member

Erin Abner, PhD


Introduction: Several maternal occupational exposures have not yet been studied for potential reproductive harm or have inconsistent findings in the literature. Despite the challenges, identification of potential risk factors, specifically reproductive toxicants, is necessary to mitigate and prevent adverse health outcomes for working mothers and their infants. The purpose of this study was to examine maternal occupational exposure to organic solvents and noise to small-for-gestational age (SGA) and preterm birth (PTB) among infants. Additionally, the study sought to examine maternal occupational exposure to noise and presence of gestational diabetes (GDM) and pregnancy-related hypertension among participant mothers.

Methods: The study population for this analysis consisted of singleton liveborn infants without birth defects (i.e., controls) who were included in the National Birth Defects Prevention Study (NBDPS), delivered between October 1,1997 and December 31, 2011, who resided in the study area in one of ten U.S. states. Unconditional logistic regression was used to estimate the association between maternal occupational exposure and birth outcome or maternal condition of interest. All statistical analyses were performed using SAS 9.4 (SAS Institute, Inc., Cary, NC) and independently replicated by a second analyst.

Results: After exclusion and eligibility criteria were met, over 7,000 participant mothers were analyzed. After adjusting for maternal education and residence at delivery, there was no increased risk of SGA or PTB associated with any occupational organic solvent exposure among participant mothers [aOR=0.93 95% CI (0.65, 1.34)]; however, there were non-significant elevated associations for maternal exposure to aromatic and Stoddard solvents and both birth outcomes [aOR=1.33 95% CI (0.74, 2.37) for aromatic solvents; aOR=1.08 95% CI (0.59, 1.99) for Stoddard solvent]. Maternal occupational exposure to the highest categorical noise levels demonstrated imprecise, but elevated associations with all birth outcomes and maternal conditions of interest [aOR=1.64 95% CI (0.91, 2.97) for SGA; aOR=1.35 95% CI (0.73, 2.48) for PTB; aOR=1.17 95% CI (0.53, 2.58) for GDM; aOR=1.61 95% CI (0.67, 3.89) for pregnancy-related hypertension].

Conclusions: Study findings suggest that maternal occupational noise exposure at levels just below where hearing protection is required or recommended—85 dBA—may be a reproductive risk factor and warrants further research. In addition, study findings contribute to the growing body of international evidence that suggest occupational exposure to organic solvents—at least at levels below the PEL—do not appear to be associated with fetal growth restriction (as measured by SGA) or PTB among infants.

Available for download on Sunday, April 14, 2024