[Risk factors for extrauterine growth restriction in preterm infants with gestational age less than 34 weeks]

To investigate the correlated factors contributed to extrauterine growth restriction (EUGR) in preterm infants with the gestational age less than 34 weeks.

A total of 694 preterm infants with the gestational ages less than 34 weeks were enrolled. They were classified into EUGR and non-EUGR groups by weight on discharge. The perinatal data, growth data, nutritional information and morbidities during hospitalization were compared between the two groups.

EUGR on discharge occurred in 284 (40.9%) out of the 694 infants. The incidence of EUGR in intrauterine growth restriction (IUGR) infants was significantly higher than in non-IUGR infants (P<0.01). The very low birth weight (VLBW) infants had a higher incidence of EUGR than non-VLBW infants (P<0.01). The incidence of EUGR increased with the decreases of gestational age at birth and birth weight (P<0.01). Compared with the non-EUGR group, the fasting time, the duration of parenteral nutrition, the time beginning to feed and the age to achieve full enteral feeds were significantly greater in the EUGR group (P<0.01). The cumulative protein deficit and cumulative caloric deficit in the first week of life in the EUGR group were higher than in the non-EUGR group (P<0.05). The incidences of respiratory distress syndrome, apnea, necrotizing enterocolitis and septicemia in the EUGR group were higher than in the non-EUGR group (P<0.05). The logistic regression analysis showed that birth weight, gestational age at birth and IUGR were the independent risk factors for EUGR.

The incidence of EUGR in infants with gestational age less than 34 weeks is high, especially in IUGR or VLBW infants. Early and aggressive nutritional strategy and prevention of apnea and septicemia may facilitate to reduce the occurrence of EUGR.