Time of the first urine and the first stool in Chinese newborns.

A total of 1,000 consecutive newborns were studied for the time of passage of the first urine and the first stool. Delayed passage (greater than 24 hours) of the first urine was noted in 4% of 920 adequate birth weight infants (birth weight greater than 2,500 grams) and 3.8% of 80 low birth weight infants (birth weight less than or equal to 2,500 grams). Whereas, delayed passage of the first stool was noted in 2.0% of adequate birth weight infants and 11.3% of low birth weight infants. By the age of 48 hours, all infants had passed their first urine, while, 99.9% of adequate birth weight infants and 97.5% of low birth weight infants had passed their first stool. There was significant difference in the gestational age, birth weight, presence of respiratory distress syndrome and delay in the first enteral feeding between the delayed and nondelayed stool passage groups.