Meta-analysis Of The Effect Of Treatment With Bacterial Vaginosis In Pregnancy On Pregnancy Outcomes

The most common clinical manifestation of abnormal vaginal flora（AVF）during pregnancy is bacterial vaginosis（BV）.BV is characterized by a dysbiosis of the vaginal microbiota where protective Lactobacillus spp.are replaced by a mixed anaerobic microbiota,including Gardnerella vaginalis and Mobiluncus spp.Morphotypes^[1-2].In pregnancy,prevalence’s between 7 and 30%have been reported depending on the study population and the definition^[3].BV may be associated with an increased risk of preterm delivery（PTD）,premature rupture ofmembrane（PROM）,chorioamnionitis and small for gestation age（SGA）^[3].However,it is controversial whether or not BV-positive pregnant women will benefit from treatment to improve the outcome of pregnancy.Some scholars believe that the treatment of BV during pregnancy can not improve the outcome of pregnancy,while others argue that only high-risk women in pregnancy benefit from screening and treatment^[4-6].Many drugs are used to treat BV,of which the most commonly used are clindamycin and metronidazole.the United States CDC also recommended these two drugs for the treatment of BV during pregnancy^[7].We will collect clinical articles on the effect of clindamycin or metronidazole treatment of woman with BV or AVF on adverse pregnancy outcomes.We will summarize and analysis the data from these articles,which is a meta-analysis.The concept of meta-analysis was first proposed by Light and Smith in 1971.Researchers had came up with completely different results for the same research at that time,They suggested that the results of small sample,single clinical trials of various therapies for a certain disease should be collected all over the world.Conduct a summary analysis to draw more realistic and scientific conclusions.Meta-analysis has gradually become the main content and research methods of"evidence-based medicine."Meta-analysis is the systematic evaluation and statistical analysis of multiple studies that are independent of each other for the same research purpose.ObjectiveWe performed a meta-analysis to evaluate the curative effect of clindamycin or metronidazole treatment of woman with BV or AVF on adverse pregnancy outcomes and hopes to play a guiding role in the clinical.MethodsIn June 2017,The Pubmed、EMBASE、CBM、The Cochrane Library and Wanfang Database were searched.We performed a meta-analysis of published,randomized clinical trials of clindamycin or metronidazole treatment of woman with BV or AVF in pregnant women.The adverse pregnancy outcomes include preterm birth（PTB）,premature rupture of membrane（PROM）and low birth weight（LBW）.The two reviewers independently extracted the data,and different opinions were resolved through discussion.All data were recorded in Rev Man 5.1.ResultsThirty-two trials were included.There were 14 researches in clindamycin compared to control group（blank or placebo）,10 researches in metronidazole compared to control group（blank or placebo）.Among the articles on the use of clindamycin compared with the control group,in addition to comparison of the effects of two groups on preterm birth,premature rupture of membranes,and low birth weight infants with BV-positive pregnant women,Part of the article comparison of the effects of two groups on preterm delivery with BV before week22,some articles studied comparison of the effect of two groups on preterm delivery with AVF in pregnant women,some articles studied the effect of two groups on preterm delivery with AVF in low-risk patients without a history of spontaneous preterm birth.Among the articles on the use of metronidazole compared with the control group,in addition comparison of the effects of two groups on preterm birth,premature rupture of membranes,and low birth weight infants with BV-positive pregnant women,Part of the article comparison of the effects of two groups on preterm delivery in high-risk patients with a history of at least one spontaneous preterm birth or in low-risk patients without a history of spontaneous preterm birth.The results showed that:（1）Treatment with clindamycin of BV-positivepregnant women at any gestationalagetheriskofpretermdeliverywas[RR=0.55,95%CI（0.34-0.89）,P=0.02].After removing the low quality article,the risk of preterm delivery was[RR=0.97,95%CI（0.60-1.56）,P=0.90].The risk of PROM was[RR=1.06,95%CI（0.28-4.05）,P=0.93]and the risk of low birth weight was[RR=0.55,95%CI（0.27-1.12）,P=0.10].（2）Treatment with clindamycin of low-risk pregnancies women with AVF at any gestational age the risk of preterm delivery was[RR=0.77,95%CI（0.54-1.08）,P=0.13].If clindamycin treatment was started before week22,the risk of preterm delivery was[RR=0.70,95%CI（0.45-1.09）,P=0.11].（3）Treatment with clindamycin of women with AVF at any gestational age the risk of preterm delivery was[RR=0.72,95%CI（0.52-1.01）,P=0.05].If clindamycin treatment was started before week22,the risk of preterm delivery was[RR=0.58,95%CI（0.41-0.84）,P=0.004].（4）Treatment with metronidazole of BV-positive pregnant women at any gestational age the risk of preterm delivery was[RR=0.49,95%CI（0.35-0.67）,P<0.00001].After removing the low quality article,the riskof pretermdelivery was[RR=0.91,95%CI（0.74-1.11）,P=0.34].The risk of PROM was[RR=0.38,95%CI（0.06-2.31）,P=0.29]and the risk of low birth weight was[RR=0.70,95%CI（0.31-1.56）,P=0.38].（5）Treatment of low-risk BV-positive pregnancies women with metronidazole at any gestational age the risk of preterm delivery was[RR=0.97,95%CI（0.79-1.20）,P=0.81].If treatment of high-risk pregnancies women the risk of preterm delivery was[RR=0.83,95%CI（0.38-1.81）,P=0.65].Conclusion（1）There is no evidence that treatment with clindamycin or metronidazole of BV-positive pregnant women can reduce the risk of preterm birth,premature rupture of membranes and low birth weight infants.（2）Clindamycin treatment women with AVF was started before week 22,the risk of preterm birth can reduce,but further research is warranted.