Longitudinal analysis of the vaginal microflora in pregnancy suggests that L. crispatus promotes the stability of the normal vaginal microflora and that L. gasseri and/or L. iners are more conducive to the occurrence of abnormal vaginal microflora

Table 5 Association between Lactobacillus type as part of grade I microflora (on culture and tRFLP) and microflora status (on Gram stain) on follow-up when accounting for the first-to-second and second-to-third trimester transitions

Lactobacillus species (culture and tRFLP) at baseline	Gram stain category on follow-up
all samples with an L. crispatus TRF (n = 83)
▪ sustained grade I microflora	97.6% (81)
▪ shift to an abnormal microflora
- grade I-like	1.2% (1)
- grade II	1.2% (1)
- grade III	-
- grade IV	-
all samples with an L. jensenii TRF (n = 42)
▪ sustained grade I microflora	92.9% (39)
▪ shift to an abnormal microflora
- grade I-like	-
- grade II	7.1% (3)
- grade III	-
- grade IV	-
all samples with an L. gasseri/iners TRF (n = 83)
▪ sustained grade I microflora	85.5% (71)
▪ shift to an abnormal microflora
- grade I-like	6.0% (5)
- grade II	7.2% (6)
- grade III	1.2% (1)
- grade IV	-

Gram stained vaginal smears were scored according to the criteria previously described by Verhelst et al [7]. Briefly, Gram-stained vaginal smears were categorized as grade I (normal) when only Lactobacillus cell types were present, as grade II (intermediate) when both Lactobacillus and bacterial vaginosis-associated cell types were present, as grade III (bacterial vaginosis) when bacterial vaginosis-associated cell types were abundant in the absence of lactobacilli, as grade IV when only gram-positive cocci were observed, and as grade I-like when irregularly shaped or curved gram-positive rods were predominant [7]. For the purpose of this study, grade I or Lactobacillus-dominated vaginal microflora is designated as 'normal vaginal microflora' and all other grades as 'abnormal vaginal microflora'.

ISSN: 1471-2180