Prenatal exposure to ambient particle radioactivity and fetal growth in Eastern Massachusetts

The radioactive component of particulate matter (PM), particle radioactivity (PR), can continue to emit radiation after inhalation. While PR has been associated with other adverse pregnancy outcomes, no studies have examined the association with fetal growth. Our retrospective cohort included singleton pregnancies that underwent obstetric ultrasounds at an academic medical center in Massachusetts from 2011 through 2016. PR was represented by particle gross beta-activity estimated from an ensemble model and was assigned based on residential zip code. We considered the cumulative (conception until date of fetal growth measurement) and first 16 weeks of gestation PR exposure windows. Standardized z-scores were constructed for biparietal diameter (BPD), head circumference, femur length (FL), abdominal circumference (AC), and birth weight. We used linear mixed regression models adjusted for PM <= 2.5 mu m exposure, maternal sociodemographic factors, meteorological variables, and long-term trends. Among 9404 pregnancies, an interquartile range increase in cumulative PR exposure was associated with reduced BPD (-0.06 [95% CI: -0.12, -0.01] z-score) and FL (-0.06 [95% CI: -0.12, -0.01] z-score) in scans conducted before 24 weeks' gestation, with increased AC (0.05 [95% CI: 0.01, 0.09]) in scans conducted on or after 24 weeks' gestation, and with lower birth weight (-0.05 [95% CI: -0.11, -0.001] z-score). The first 16 weeks of gestation was not a critical exposure window. Prenatal PR was associated with fetal growth, with associations generally negative before 24 weeks' gestation and positive later in pregnancy. Our findings bring awareness to a novel environmental exposure.

Automated summary

This study retrospectively examined the association between particle radioactivity (PR) and fetal growth in pregnancies. The results showed that PR exposure was negatively associated with fetal growth before 24 weeks' gestation and positively associated after 24 weeks. This study highlights the importance of considering environmental exposure on fetal development.