[Analysis of related factors of extremely preterm infants'abnormal neurological findings]

To observe the effect of intrapartum and postpartum factors on abnormal neurological findings in the extremely preterm infants.

Clinical data of 62 premature infants (33 of male, 29 of female) were retrospectively analyzed. None of the premature infants had birth defect; their gestational ages were all less than 28 weeks (23(+ 6)-27(+ 6) weeks). They were hospitalized within 12 hours after birth in the neonatal intensive care unit (NICU) of BAYI Children's Hospital from November 2010 to June 2013. The blood gas, birth condition, complications, the mechanical ventilation and the ultrasonic encephalography were recorded. The 62 cases were divided into 2 groups, alive group and died group. Meanwhile, all cases of survial were divided into brain injuries group and normal brain group. Data were analyzed with t-test, Chi square test and Spearman correlation analysis.

Fifty-six cases were alive, and 6 cases died (3 were during the treatment and 3 were after parents gave up). The average birth weight of brain injuries group was (954 ± 182) g; and that of the normal brain group was (1 071 ± 136) g. There were significant differences between the two groups in gender (χ(2) = 4.314, P = 0.038), gestational age (χ(2) = 11.622, P = 0.001), birth weight (t = 2.728, P = 0.009), which had significant correlation with neurological outcomes. The Spearman correlative coefficients were -0.278, 0.456 and 0.364 respectively. And P values were 0.038, 0.000 and 0.006. The rates of multiple pregnancy, lung hemorrhage and surgical operation in brain injuries group were 45%(9/20), 55%(11/20), 40%(8/20), which were significantly higher than those in normal brain group, 3%(1/36), 17%(6/36), 11%(4/36)(χ(2) = 12.800, 8.936, 4.773, P all < 0.05). These three factors were the high risk factors for adverse neurological outcomes, the odds ratios were 28.64, 6.11 and 5.33 respectively. There was no significant difference in delivery mode, amniotic fluid, maternal infection, asphyxia, necrotizing enterocolitis, patent ductus arteriosus, sepsis, mechanical ventilation, inhaled nitric oxide therapy, blood glucose, blood gas analysis, doses of dopamine between brain injuries group and normal brain group. The birth weight in alive group was (1 029 ± 163) g, which was significantly higher than those in died group (870 ± 144)g (r=0.29, P=0.022). There was no significant difference in other factors between alive group and died group(P all>0.05).

Gender, gestational age and birth weight may have relation with the neurological outcomes of extremely preterm infants. Multiple pregnancy, pulmonary hemorrhage and surgical operation are the risk factors of brain injuries. Birth weight is related to the survival of extremely preterm infants.