727 - Early Stool Patterns as Predictors of Feeding Tolerance, Growth, and Bowel Injury in Extremely Preterm Infants

Publication Number: 727.4750

Erin Y. Kim, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Sepideh Saroukhani, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Covi Anne Tibe, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Matthew Rysavy, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Lindsay F. Holzapfel, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States; Mar Romero-Lopez, University of Texas Health Science at Houston, Houston, TX, United States

Background: Extremely premature infants often experience delayed meconium passage and feeding intolerance, possibly affecting feeding progression, infant growth, and abdominal complications such as necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP).

Objective: This study investigates the relationships between stool patterns, feeding practices, growth, and bowel injury in the most extremely preterm infants.

Design/Methods: This retrospective cohort study included infants born between 22-25 weeks gestational age admitted to a Level IV NICU from 2020 to 2023. Stool patterns were categorized by day of first meconium stool after birth (Early ≤3, Intermediate 4-7, Late >7), day of first non-meconium stool after birth (Early ≤7, Intermediate 8-14, Late >14), and stool frequency in the first 14 days after birth (Low < 7, Medium 7-14, High >14). We assessed associations of feeding practices, growth variables, and incidence of NEC and SIP with stool patterns using ANOVA or Kruskal-Wallis Test (Table 1 and Figure 1).

Results: Of the total 212 infants, mean gestational age was 24.4 ± 1.0 weeks and mean birth weight was 686 ± 148.5 grams (Table 2). Almost half of the infants (48%) had intermediate meconium timing (4-7 days), 68% had intermediate non-meconium stool timing (8-14 days), and 73% had high stool frequency (>14). Early meconium timing (≤3 days) compared to intermediate (4-7 days) and late (>7 days) was associated with earlier enteral feeding by 1 day (p < 0.01). Fortification was delayed with late meconium timing (>7 days) compared with early (≤3 days) by 1 week (p=0.01). Late non-meconium stool (>14 days) and low stool frequency ( < 7) were linked to delays in reaching ≥120 ml/kg feed volume and fortification compared to early non-meconium stool (≤7 days) and high stool frequency (>14) (p < 0.01). Birth weight recovery was later with intermediate meconium timing (4-7 days) compared to late (>7 days) (p=0.03). Infants with low stool frequency ( < 7) had lower length and head circumference z-scores (-2.9 ± 0.8, -2.9 ± 0.7) compared to the high-frequency (>14) group (-2.1 ± 0.9, -1.9 ± 1.2, p=0.02). The incidence of NEC (Modified Bells Criteria ≥Stage 2A) was 23% and SIP was 6%. High stool frequency (>14) indicated lower risk of SIP compared to low frequency ( < 7) (RR 0.03 (CI 0.003, 0.24), p< 0.01).

Conclusion(s): Stool patterns are associated with feeding practices and growth in infants born at 22-25 weeks gestation. Further research is needed to determine if these associations are causal and if interventions to facilitate stool passage in this population would impact feeding, growth, or bowel injury.

Table 1. Stool Patterns and Associated Growth, Birth Weight Recovery, Feeding, and Bowel Injury Outcomes in Preterm Infants 22-25 Weeks Gestation


Table 2. Neonatal Characteristics and Perinatal History by Meconium Timing Groups in Preterm Infants 22-25 Weeks Gestation


Figure 1. Stool Timing and Frequency in Preterm Infants 22-25 Weeks Gestation
The boxes represent the interquartile range, containing the middle 50% of the data. The horizontal line within each box indicates the median. The “X” inside each box indicates the mean. Whiskers extend to the minimum and maximum values, excluding outliers. Individual dots represent outliers. Asterisk represents significance between the two groups at the end of each bracket. Values below are presented as Median (IQR). Abbreviations: NEC = necrotizing enterocolitis, SIP = spontaneous intestinal perforation.
A. The SIP and control group showed the broadest range of passage times for meconium stool while the SIP group showed the broadest range for time to first non-meconium stool. The control and NEC groups had similar median times for meconium (5 (2,6), 5 (2,6)) and non-meconium (9 (7, 11), 9 (7, 11)) passage. The SIP group exhibited earlier median time for meconium (4 (1,7)) and non-meconium (7 (5,10)) passage (p>0.05).
B. The control group showed the broadest range of stool frequency over the first 14 days after birth, and the SIP group showed the smallest range of stool frequency. The median stool frequency for control (24 (14, 33)) and NEC (22 (11, 28.5)) groups were similar, but the median for the SIP group (6 (2, 9)) was lower compared to control and NEC (p < 0.01).