Effect of perinatal group B streptococcus carriers in late pregnancy on pregnancy outcome

Objective To investigate the group B streptococcus（ GBS）colonization rate and the relationship between vaginal colonization of GBS and the pregnancy outcome. Methods Five hundred and twenty cases pregnant women were selected as our subjects. Microbiological culture was used for culture of GBS in 1 / 3 of vagina and rectus before delivery,other samples from different sites after delivery（including neonatal throat,ear and placenta）. Results （1）The GBS carrier rate in 520 pregnant women was 10. 19%（53 / 520）. （2）GBS carrier rate in neonatal was 8. 85%（46 / 520）. The carrier rate of neonatal whose mothers also carried GBS was 22. 64%（12 / 53）,higher than that of non-carrier mothers（7. 28%（34 / 467）,χ^2 = 8. 192,P 〈 0. 05） . The rate of pneumonia and the upper respiratory tract infection of neonatal with GBS-carrier-mother were 20. 75%（11 / 53）and 18. 87%（10 / 53）,higher than that of non-carrier mothers（8. 57%（40 / 467）and 4. 71%（22 / 467））. The pneumonia rate and upper respiratory tract infection of GBS positive neonatal were 21. 73%（10 / 46）and 19. 56%（9 / 46）,higher than GBS negative one（8. 65%（41 / 474）;4. 85%（23 / 474））. and there were significant differences（χ^2 = 8. 121,15. 717;P 〈 0. 05）.（3）The incidence of intrauterine infection and fetal distress of neonatal with GBS（ ＋ ）mother were 47. 17%（25 / 53）,15. 09%（8 / 53）,significantly higher than that of negative（7. 07%（33 / 467）,4. 71%（22 / 467））,and the differences were statistically significant（ χ^2= 77. 248,9. 440;P 〈 0. 05）. But there were the similar incidence in term of premature rupture of fetal membranes,premature occurrence rate between GBS positive and negative mothers（ 28. 30%（ 15 / 53 ） vs. 28. 48%（133 / 467;3. 77%（2 / 53）vs. 2. 36%（11 / 467）;χ^2 = 0. 001,0. 393;P 〉 0. 05）. The rate of GBS positive with mycotic vaginitis,placenta previa ratio were 39. 62%（21 / 53）,7. 55%（4 / 53）,higher than that of GBS negative one（20. 56%（96 / 467）,1. 93%（9 / 467））,and the differences were statistically significant（χ^2= 9. 922,6. 168,P 〈 0. 05）. Conclusion Maternal GBS carrier at 35 - 37 weeks of gestation can lead to adverse pregnancy outcome by increasing intrauterine infection fetal distress and neonatal infections. Screening of GBS should be performed routinely in late gestation. Key words: Late pregnancy; Group B streptococcus; Pregnancy outcome