Exploration On Risk Factors Of Histological Chorioamnionitis And Its Relationship With Recent Complications In Premature Infants

Objective:To explorate risk factors of histological chorioamnionitis（HCA）and its relationship with recent complications in premature infants.Methods:We collected the data of premature infants who were born in the obstetrics department from 1st January,2018 to 31st December,2020 and hospitalized in the Neonatal Department of the Second Affiliated Hospital of Guangxi Medical University with placental pathology examinations performed at 28～36⁺⁶weeks and their pregnant mothers.According to the results of placental tissue examination,they were divided into a HCA group and a non-chorioamnionitis（NCA）group.The HCA group were further divided into mild,moderate and severe HCA groups based on the degree of inflammation seen during placental histology examinations.Analyzed the incidence of HCA,clinical indicators of premature infants,clinical features of their mothers,and the relationship between HCA and premature rupture of membranes（PROM）,the occurrence of complications in premature infants under different gestational age stratification,also the occurrence of the complications of premature infants with different HCA severity and risk factors for HCA occurrence were analyzed.All data were analyzed by using SPSS 23.0 and P<0.05 was considered to be statistically significant.Results:1.Case inclusion:456 premature infants included in the study during the period,222 cases（48.7%）underwent placental pathology examination,158 cases（71.1%）were diagnosed with HCA,excluded 46 cases whose medical records were incoplete.Finally,176 cases were included,,and there were 120 cases of HCA（84 mild,26 moderate and 10 cases of severe HCA）and 56 cases of NCA.46 cases with incomplete case data were excluded.46cases with incomplete case data were excluded,176 premature infants were finally included.Of the 176 premature infants,there were 120 cases of HCA（84mild,26 moderate and 10 cases of severe HCA）and 56 cases of NCA.2.Clinical indicators for premature infants:The mean gestational age and birth weight of premature infants in the HCA group were（34.23±2.23）weeks and（2165.17±555.24）g,respectively,compared with（34.27±2.06）weeks and（2068.75±464.86）g in the NCA group,and there were no significant differences（P>0.05）.There were no significant differences in sex ratio,intrauterine distress,small for gestational age,admission to the neonatal critical care unit,use of lung surface active substances,use of invasive ventilator,oxygen use time,less than or equal to 7 points in 1 min Apgar score and 5min Apgar score,time of parenteral nutrition,antibiotic use and its duration between HCA and NCA groups.3.HCA and gestational age:Of the 176 included preterm infants,the gestational age ranged from 28 to 31⁺⁶weeks in 22 cases,and the incidence of HCA was 72.7%;34 cases were distributed at 32～33⁺⁶weeks,and the incidence of HCA was 73.5%;120 cases were distributed at 34-36⁺⁶weeks,and the incidence of HCA was 73.5%.The incidence of HCA in different gestational age groups was not statistically significant（P>0.05）.Spearman correlation analysis showed that gestational age was negatively correlated with the severity of HCA（r=-0.165,P<0.05）.4.Clinical indicators of pregnant women:the incidence of PROM in the HCA group was 41.7%（50/120）,and the rate of prenatal antibiotic use was34.2%（41/120）,both of which were significantly higher than that in NCA group(23.2（13/56）and 17.9%（10/56）compared to the NCA group（P>0.05）.The differences in age,cesarean section,gestational order,delivery order,placental abruption,parturient women,oligohydramnios,turbid amniotic fluid,gestational diabetes mellitus,prenatal glucocorticoid application,placenta previa,prenatal fever and gestational hypertension in the two groups showed no statistical significance（P>0.05）.5.HCA and PROM:The total incidence of PROM in 176 preterm infants of this study was 35.8%.PROM time was divided into different time groups,Ⅰ,,Ⅲ,ⅣandⅤwhich were respectively defined as no PROM time,<24h PROM time,24h≤PROM time≤48h,48h<PROM time<7d and≥7d PROM time.The incidence of HCA in theⅠ,Ⅱ,Ⅲ,ⅣandⅤgroups were 61.4（70/114）,77.8（21/27）,83.3（10/12）,89.5（17/19）and 50%（2/4）,respectively.TheⅠ,Ⅱ,ⅢandⅣgroups showed an increasing trend in the incidence of HCA and groupⅤhad the lowest incidence of HCA.Spearman correlation analysis was performed with different degrees of placental inflammation and PROM times,and this showed that PROM time was positively correlated with the severity of placental inflammation（r=0.253,P>0.05）.6.Laboratory indicators:White blood cell（WBC）counts and neutrophil percentages（NEU%）of pregnant women in the HCA group respectively were（10.47±2.86）×10⁹/L and（0.747±0.091）,respectively,which were both higher than those in NCA group which were（9.55±2.52）×10⁹/L and（0.704±0.076;P>0.05）.There were no statistical significances in the prenatal hemoglobin of pregnant mothers,WBC,NEU%,hemoglobin and platelet of premature infants on the first day after birth,hemoglobin,platelets and WBC and NEU%of premature infants on the third day after birth between the two groups（P<0.05）.7.Recent observed complications of premature infants:Recent observed complications of premature infants:the most common 3 diseases in HCA and NCA groups were neonatal early anemia[82 cases（68.3%）in the HCA group,27 cases（48.2%）in the NCA group],neonatal pneumonia[60 cases（50%）in the HCA group,30 cases in NCA group（53.6%）]and respiratory distress syndrome（RDS）[35 cases in HCA group（29.2%）and 26 cases in NCA group（46.4%）].The incidence of neonatal hypoglycemia in HCA group was 11.7%（14/120）significantly lower than that in NCA group（30.4%,17/56）,and the differences were statistically significant（P<0.05）.The incidence of neonatal sepsis,neonatal pneumonia,neonatal necrotizing enterocolitis,periventricular/intraventricular hemorrhage（PIVH）,shock,suppurative meningitis,patent ductus arteriosus and bronchopulmonary dysplasia between the two groups were not statistically significant（P>0.05）.8.HCA and RDS:The incidence of RDS in the HCA group was significantly lower than that in the NCA group,and the difference was statistically significant（P<0.05）.The incidence of RDS in mild HCA was significantly lower than that in moderate HCA,severe HCA and NCA,and the difference was statistically significant（P<0.05）.The incidence of RDS in the HCA group increased with the aggravation of placental inflammation.When adjusted for gestational age,there was no significant correlation between the different levels of HCA and the occurrence of RDS（P>0.05）.9.Binary Logistic regression showed that PROM[OR=0.423,95%CI（0.206-0.868）]is a risk factor for HCA（P<0.05）.Placenta previa,gestational age,gestational diabetes mellitus,oligohydramnios,maternal age,prenatal glucocorticoid application,placental abruption and gestational hypertension were not significantly associated with HCA（P>0.05）.Conclusions:1.The incidence of HCA is high in premature infants,which should be paid more attention in clinical practice.2.The occurrence of HCA was not related to mean gestational age.Gestational age may be related to the severity of HCA,and severe HCA is more common in premature infants of small gestational age.3.PROM was a risk factor for the occurrence of HCA and the longer the PROM time,the more severe the occurrence of HCA.4.HCA may lead to a decrease in RDS,and mild HCA was found to be associated with a reduction in the incidence of RDS.