NICU Medical Device Use Linked to Bisphenol A Exposure

Joe Barber Jr, PhD

February 18, 2013

Among infants receiving care in a neonatal intensive care unit (NICU), the number of medical devices used may be associated with their level of exposure to bisphenol A (BPA), according to the findings of an exposure assessment study.

Susan M. Duty, ANP-BC, MSN, ScD, from Simmons College in Boston, Massachusetts, and colleagues published their findings online February 18 and in the March issue of Pediatrics.

BPA is an environmental endocrine disrupter, which is known to leach out of polycarbonate plastics. Although developing fetuses and young infants may be particularly vulnerable to endocrine disrupters, few studies have focused on their exposure.

"Medical devices made from polycarbonate plastic such as intravenous administration sets, stopcocks, syringes, intravascular catheters, urinary catheters, gastrointestinal tubes, and cardiopulmonary bypass circuits are sources of exposure to BPA," the authors write. "Data on medical devices as sources of BPA exposure to premature infants in NICU settings are scarce."

In the study, the researchers recruited mother/infant pairs and measured the urinary BPA concentrations of the infants after stratifying them according to medical device use. To be eligible, infants had to spend at least 3 consecutive days in the NICU, and mothers had to be over 18 years of age and speak English. The authors excluded infants with hepatic or renal failure or genetic abnormalities.

Among the 55 infants born to 43 mothers, infants who required 4 or more medical devices had much higher BPA levels than infants who required 3 or fewer devices (36.6 μg/L [95% confidence interval (CI), 17.2 - 47.3 μg/L] vs 13.7 μg/L [95% CI, 9.2 - 35.1 μg/L]; P = .01).

Median urinary BPA concentrations increased with decreasing gestational age (4.3 μg/L at >37 weeks, 12.4 μg/L at 32 - 36 weeks, and 34.2 μg/L at <32 weeks; P < .001) and decreasing birth weight (9.2 μg/L among normal-weight, 12.7 μg/L for low-birth-weight, and 36.6 μg/L for very low-birth-weight infants; P < .001). Boys were more likely to have a gestational age of less than 32 weeks (73% vs 40%; P = .01) and to have higher BPA levels (24.9 vs 13.7 μg/L; P = .03)

No significant difference in BPA concentration was noted between breast milk– and formula-fed infants (23.3 μg/L [95% CI, 12.8 - 40.8 μg/L] vs 13.1 μg/L [95% CI, 9.2 - 40.6 μg/L]).

In a mixed-effects regression model adjusted for nutritional intake, medical device use, sex, and gestational age, infants whose care included 4 or more medical devices had 1.6-fold higher (95% CI, 1.01 - 2.58 times; P = .045) BPA concentrations than those whose care included 3 or fewer devices.

"This study provided detailed information on the duration of use of specific medical devices and estimation of the nutritional intake of BPA from either maternal milk or formula," the authors write. "[T]he degree of prematurity and gender remained strong significant independent predictors of urinary BPA concentrations even after adjustment for device use and nutritional exposure, indicating the need for additional research into other potential determinants in the NICU including the microenvironment of the isolette."

This study was supported by the National Institutes of Health, the Harvard School of Public Health–National Institute of Environmental Health Sciences Center for Environmental Health, and from the Passport Foundation, Science Innovation Fund. One coauthor was supported by a Harvard School of Public Health–National Institute of Environmental Health Sciences Pilot grant. The other authors have disclosed no relevant financial relationships.

Pediatrics. 2013;131:483-489.