Time of first stool in extremely low birth weight (< or = 1000 grams) infants.

The time of first stool was studied in 144 infants with a birth weight of 1000 gm or less. Median age at passage of the first stool was 3 days, and 90% of the infants passed stool by 12 days after birth. There was no relationship between the time of passage of the first stool and either birth weight or gestational age. Of the 114 infants, 88 (77%) passed stool before the initiation of any enteral feeding. The passage of the first stool was delayed in male compared with female infants (p = 0.03).