(Open access funding provided by Semmelweis University)
Prematurity is the leading cause of perinatal mortality and the morbidity among children
under the age of 5. The prevalence of preterm birth is between 5 and 18% worldwide.
Approximately 30% of preterm deliveries occur as a consequence of fetal or maternal
infections. Bacterial vaginosis can increase the risk of ascending infections. However,
there is no recommendation or protocol for screening of abnormal vaginal flora. The
aim of this systematic review was to investigate the effectiveness of routine screening
of abnormal vaginal flora during pregnancy care. We conducted our systematic search
in the following databases: MEDLINE via PubMed, Embase, and Cochrane Library. Studies
reporting on pregnant women with no symptoms of bacterial vaginosis were included
in our analysis if they provided data on the outcome of their pregnancy. The intervention
group went through screening of abnormal vaginal flora in addition to routine pregnancy
care. Odds ratio (OR) with 95% confidence intervals (CIs) was used as effect size
measure. From each study the total number of patients and number of events was extracted
in both the intervention and control arm to calculate OR. Altogether we included 13
trials with 143,534 patients. The screening methods were Gram stain, pH screening,
pH self-screening and pH screening combined with Gram stain. Regular screening of
vaginal flora compared to no screening significantly reduces the odds of preterm birth
before 37 weeks (8.98% vs 9.42%; OR 0.71, CI 0.57-0.87), birthweight under 2500 g
(6.53% vs 7.24%; OR 0.64, CI 0.50-0.81), preterm birth before 32 weeks (1.35% vs 2.03%;
OR 0.51, CI 0.31-0.85) and birthweight under 1000 g (0.86% vs 2.2%; OR 0.33, CI 0.19-0.57).
In conclusion, the routine screening of abnormal vaginal flora might prevent preterm
birth, extreme preterm birth, low birthweight deliveries and very low birthweight
deliveries. Further research is needed to assess the problem more accurately.
