Aim To determine the exposure of VLBW infants to phthalates during their stay in the neonatal intensive care unit.
Method Preterm infants (< 32wks and/or < 1500g), who stayed in the NICU >2 wks and had at least one invasive procedure were included. Urine samples were collected in the first 3 days and every 2 weeks until discharge. Phthalate contents of the medical devices, urinary excretion of phthalate metabolites. (diethylhexylphthalate-DEHP, monoethylhexylphthalate-MEHP, monoethyloxohexylphthalate-MEOHP, monoethylhydroxyhexylphthalate-MEHHP) and their relation to exposure intensity, gestational age, birthweight and postnatal age were analysed.
Result Mean gestational age and birth weight of the patients (n=36) were 28.9±1.5wks and 1024±262g. DEHP was detected in umbilical catheters, intubation tubes, nasogastric tubes and nasal cannulas. Nasal cannulas had the highest content (201.7mg/0.5g). MEHHP was the most frequently detected metabolite (81.4%) in the urine samples (n=151) and its levels increased during the first 4 weeks (mean concentration: 319.5 ng/ml), were higher in patients who had continuing need of invasive procedures after 2 wks (255.32 ng/ml vs 65.85 ng/ml), were significantly higher in the first urine samples of patients < 1000g compared to those ≥1000g (63.17±93.79 ng/ml vs 10.93±22.98 ng/ml, p=0.001).
Conclusion Phthalate metabolites could be detected in the urine samples of preterm infants very early after admission to the NICU. The levels were higher in the first weeks of intensive care when exposure intensity was highest and in babies < 1000g. Monoethylhydroxyhexylphthalate-MEHHP may be the most suitable biomarker of phthalate exposure.