Effect Of Group B Streptococcus Infection In Late Pregnancy On Premature Rupture Of Membranes And Pregnancy Outcome

Objective:To study the effect of group B streptococcus infection in late pregnancy on premature rupture of membranes and pregnancy outcome Methods:267 pregnant women with PROM in late pregnancy who delivered in the obstetrics department of the first hospital of Jilin University from January 2021 to January 2022 were selected as the case group,and 388 healthy pregnant women who delivered in the same period were randomly selected as the control group.The general data of the two groups of pregnant women were collected,including delivery age,intrapartum body mass index（BMI）,mode of pregnancy,times of delivery,abortion history,delivery（gestational weeks,mode of delivery,amniotic fluid properties,Apgar score,transfer to neonatal Pediatrics）Maternal and fetal complications（postpartum hemorrhage,puerperal infection,chorioamnionitis,neonatal asphyxia,neonatal sepsis,neonatal infection,neonatal infectious pneumonia,neonatal respiratory distress syndrome,neonatal GBS infection）,laboratory examination（leukocyte count,absolute value of neutrophils,PCR group B streptococcus infection）.In addition,the time from rupture of membranes to delivery,the results of amniotic fluid bacterial culture and high-sensitivity C-reactive protein（CRP）were collected.The relationship between group B streptococcal infection and premature rupture of membranes and its impact on maternal and fetal pregnancy outcomes were statistically analyzed.Result:（1）The delivery age of 267 pregnant women in the case group was 18-44 years old,with a median age of 31 years.The age of 388 pregnant women in the control group was 21-49 years old,and the median age was 30 years old.There was no significant difference between the two groups in delivery age,BMI at delivery,mode of pregnancy and abortion history（P > 0.05）;193primiparas（72.28%）in the case group,74 primiparas（27.72%）,319 primiparas（82.22%）and 69 primiparas（17.78%）in the control group.The proportion of primiparas in the case group was significantly higher than that in the control group（P < 0.05）.（2）The white blood cell count,absolute value of neutrophils and GBS infection between the two groups were counted.There were 31 GBS positive pregnant women（11.61%）in the case group and 58 GBS positive pregnant women（14.95%）in the control group.There was no significant difference in white blood cell count,absolute value of neutrophils and positive rate of GBS infection between the two groups（P > 0.05）.（3）Among the 267 cases in this study,the gestational week of delivery was 36-41.57 weeks,the median gestational week was 39 weeks,109 cases of vaginal delivery,accounting for 40.82%,158 cases of cesarean section,accounting for 59.18%,26 cases of fecal contamination of amniotic fluid of pregnant women,accounting for 9.74%,Apgar 1-minute score was 3-10,the median score was 10,Apgar 5-minute score was 7-10,the median score was 10,and 91 cases were transferred to neonatal Pediatrics,accounting for 34.08%.Among the 388 Cases in the control group,the gestational week of delivery was 36-42.14 weeks,the median gestational week was 39.5 weeks,175 cases of vaginal delivery,accounting for 45.1%,213 cases of cesarean section,accounting for 54.9%,47 cases of fecal contamination of amniotic fluid,accounting for 12.11%,Apgar 1-minute score was 6-10,the median score was10,Apgar 5-minute score was 8-10,the median score was 10,and 43 cases were transferred to neonatal Pediatrics,accounting for 11.08%.The gestational weeks of delivery in the case group were less than those in the control group,the Apgar score was lower than that in the healthy group,and the proportion of transferred to neonatal Pediatrics was higher than that in the control group（P <0.05）.（4）The maternal complications of the two groups showed that 25 patients in the case group had postpartum hemorrhage,accounting for 9.36%,2 cases of puerperal infection and 2 cases of chorioamnionitis.In the control group,there were only 10 cases of maternal complications and postpartum hemorrhage,accounting for 2.58%.There was significant difference in the incidence of postpartum hemorrhage between the two groups（P < 0.05）.Comparing the neonatal complications between the two groups,there were 13 cases of neonatal asphyxia,accounting for 4.87%,11 cases of neonatal sepsis,accounting for 4.12%,and 5 cases of neonatal respiratory distress syndrome,accounting for 1.87%.There were significant differences in neonatal asphyxia,neonatal sepsis and neonatal respiratory distress syndrome between the two groups（P < 0.05）.（5）267 cases of premature rupture of membranes with gestational weeks ≥36 weeks were included in this study.The time from rupture of membranes to delivery was 1.5-70 h,with a median time of 11 h.Among them,197 cases（73.78%）delivered within 18 hours of rupture of membranes,and 70 cases（26.22%）delivered within 18 hours of rupture of membranes.Among the patients with premature rupture of membranes,31 cases were diagnosed with GBS infection,accounting for 11.61%.Among them,29 cases of group B Streptococcus were detected by PCR,8 cases of Streptococcus agalactiae were cultured in amniotic fluid,and 2 cases of group B Streptococcus were cultured in amniotic fluid,but the PCR results showed that group B streptococcus was negative.Considering that the PCR results were false negative due to too little sample template content,these 2 cases were included in the GBS infection group.Among the 267 patients in the case group,153 cases showed positive amniotic fluid culture results,of which 86（32.21%）pregnant women had one pathogen,45（16.85%）had two pathogens,and 22（8.23%）had three or more pathogens.Coagulase negative Staphylococcus was the main pathogen cultured in amniotic fluid,including 54 cases of Staphylococcus epidermidis.Gram positive cocci were the second largest group of pathogens detected in amniotic fluid,of which Streptococcus viridis（55 cases）accounted for the most,followed by Streptococcus agalactiae（8 cases）.（6）The detection of GBS in patients with premature rupture of membranes can be carried out by real-time fluorescence quantitative PCR and / or amniotic fluid bacterial culture.The results of this study showed that the positive detection rate of GBS by PCR was 10.86% and that by bacterial culture was3%.The difference was statistically significant（P < 0.05）.（7）Maternal complications occurred in 29 of 267 patients with premature rupture of membranes.The results showed that compared with the non complication group,the proportion of rupture of fetal membrane to delivery time > 18 h in the complication group was higher,and the difference was statistically significant（P < 0.05）.Taking maternal complications as dependent variable and variables with P < 0.2 in univariate analysis as independent variable,binary logistic regression analysis was used.The results showed that the time from rupture of membranes to delivery ≥ 18 h was an independent factor leading to maternal complications in patients with premature rupture of membranes（P < 0.05）.（8）Among 267 newborns,26 cases had neonatal complications.There was significant difference in maternal GBS infection compared with no neonatal complications（P < 0.05）.Based on the results of univariate analysis between the two groups,the variables with P < 0.2 were included in the binary logistic regression model for regression analysis.The results showed that the maternal delivery age ≥ 35 years old and maternal GBS infection were the risk factors of neonatal complications in patients with premature rupture of membranes（P <0.05）.（9）267 pregnant women with premature rupture of membranes can be divided into 31 cases in GBS positive group and 236 cases in GBS negative group according to whether the mother has GBS infection.The proportion of GBS positive newborns transferred to neonatal Pediatrics,neonatal sepsis,neonatal infection and neonatal respiratory distress syndrome was significantly higher than that in GBS negative group（P < 0.05）.Conclusion:（1）Delivery age ≥ 35 years old is the risk factor of neonatal complications.（2）The risk of adverse outcomes such as neonatal sepsis,neonatal infection and neonatal respiratory distress syndrome is high when pregnant women with premature rupture of membranes are infected with GBS;（3）The time from rupture of membranes to delivery is more than 18 hours,which is the risk factor of maternal complications.（4）The positive rate of GBS infection screened by PCR is higher than that of amniotic fluid culture,which is suitable for routine screening.（5）Pregnant women at 36 weeks of gestation can be routinely screened for GBS,and pregnant women with premature rupture of membranes can be cultured with amniotic fluid bacteria.