Hidden Toxicity in Neonatal Intensive Care Units: Phthalate Exposure in Very Low Birth Weight Infants.
OBJECTIVE
To determine exposure to endocrine-disrupting phthalates in preterm infants in neonatal intensive care units (NICU).


METHODS
Urine samples (n=151) from 36 preterm infants (<32 weeks of gestation and/or <1500 g of birth weight) were collected on the first 3 days of admission to the NICU and biweekly thereafter. Diethylhexyl phthalate contents of indwelling medical devices used in various procedures and the concentrations of phthalate metabolites in the urine samples were analyzed. The relationships between urinary excretion, exposure intensity, postnatal age and birth weight were examined.


RESULTS
The mean gestational age and mean birth weight of the study infants were 28.9±1.5 weeks and 1024±262 g, respectively. Diethylhexyl phthalate was detected in umbilical catheters, endotracheal tubes, nasogastric tubes, and nasal cannula. Monoethylhydroxyhexyl phthalate (MEHHP) was the most frequently detected metabolite (81.4%); its concentration increased during the first 4 weeks and then started to decrease but never disappeared. Patients who did not need indwelling catheters (except nasogastric tubes) after 2 weeks were classified as group 1 and those who continued to have indwelling catheters as group 2. Although not of statistical significance, MEHHP levels decreased in group 1 but continued to stay high in group 2 (in the 4th week, group 1: 65.9 ng/mL and group 2: 255.3 ng/mL). Levels of MEHHP in the first urinary samples were significantly higher in infants with a birth weight <1000 g (<1000 g: 63.2±93.8 ng/mL, ≥1000 g: 10.9±22.9 ng/mL, p=0.001).


CONCLUSIONS
Phthalate metabolites were detected even in the first urine samples of very low birth weight newborns. Phthalate levels were higher in the first weeks of intensive invasive procedures and in preterm infants with a birth weight less than 1000 g. MEHHP was the most frequently detected metabolite and could be a suitable biomarker for the detection of phthalate exposure in preterm infants.
İstanbul University İstanbul Faculty of Medicine, Department of Pediatrics, Division of Neonatology, İstanbul, Turkey, Phone: +90 505 328 72 08 E-mail: atalaydemirel@yahoo.com.
Atalay
A
Demirel
Asuman
A
Çoban
Şükran
Ş
Yıldırım
Canan
C
Doğan
Rukiye
R
Sancı
Zeynep
Z
İnce
D015415:Biomarkers / Q000652:urine*; D001724:Birth Weight; D002853:Chromatography, Liquid / Q000379:methods; D004051:Diethylhexyl Phthalate / Q000378:metabolism / Q000506:poisoning / Q000652:urine*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000652:urine; D019102:Infant, Very Low Birth Weight / Q000652:urine*; D007363:Intensive Care Units, Neonatal; D008297:Male; D010968:Plasticizers / Q000378:metabolism / Q000506:poisoning; D053719:Tandem Mass Spectrometry / Q000379:methods
D015415:Biomarkers; D010968:Plasticizers; D004051:Diethylhexyl Phthalate