Abnormal vaginal flora correlates with pregnancy outcomes: A retrospective study from 737 pregnant women

Vulvovaginitis in pregnant women

• The balanced vaginal microbiome is the main factor defending the vaginal environment against infections. Lactobacilli play a key role in this regard, maintaining the vaginal pH within the normal range (3.8 to 4.5). •Hormonal and immune adaptations resulting from pregnancy influence changes in the vaginal microbiome during pregnancy. •An altered vaginal microbiome predisposes to human immunodeficiency virus (HIV) infection. •Bacterial vaginosis is the main clinical expression of an imbalanced vaginal microbiome. •Vulvovaginal candidiasis depends more on the host's conditions than on the etiological agent. •Trichomonas vaginalis is a protozoan transmitted during sexual intercourse. •The use of probiotics is not approved for use in pregnant women.

Vulvovaginal yeast infections during pregnancy and perinatal outcomes: systematic review and meta-analysis

BACKGROUND

Vulvovaginal yeast infections in pregnancy are common and can cause extensive inflammation, which could contribute to adverse pregnancy outcomes. Symptomatic yeast infections are likely to cause more inflammation than asymptomatic. The objective of this study was to investigate associations between symptomatic and asymptomatic vulvovaginal yeast infections in pregnancy and perinatal outcomes.

METHODS

We did a systematic review and searched eight databases until 01 July 2022. We included studies reporting on pregnant women with and without laboratory confirmed vulvovaginal yeast infection and preterm birth or eight other perinatal outcomes. We used random effects meta-analysis to calculate summary odds ratios (OR), 95% confidence intervals (CI) and prediction intervals for the association between yeast infection and outcomes. We described findings from studies with multivariable analyses. We assessed the risk of bias using published tools.

RESULTS

We screened 3909 references and included 57 studies. Only 22/57 studies reported information about participant vulvovaginal symptoms. Preterm birth was an outcome in 35/57 studies (49,161 women). In 32/35 studies with available data, the summary OR from univariable analyses was 1.01 (95% CI 0.84-1.21, I2 60%, prediction interval 0.45-2.23). In analyses stratified by symptom status, we found ORs of 1.44 (95% CI 0.92-2.26) in two studies with ≥ 50% symptomatic participants, 0.84 (95% CI 0.45-1.58) in seven studies with < 50% symptomatic participants, and 1.12 (95% CI 0.94-1.35) in four studies with asymptomatic participants. In three studies with multivariable analysis, adjusted ORs were greater than one but CIs were compatible with there being no association. We did not find associations between vulvovaginal yeast infection and any secondary outcome. Most studies were at high risk of bias in at least one domain and only three studies controlled for confounding.

CONCLUSIONS

We did not find strong statistical evidence of an increased risk for preterm birth or eight other adverse perinatal outcomes, in pregnant women with either symptomatic or asymptomatic vulvovaginal yeast infection. The available evidence is insufficient to make recommendations about testing and treatment of vulvovaginal yeast infection in pregnancy. Future studies should assess vulvovaginal symptoms, yeast organism loads, concomitant vaginal or cervical infections, and microbiota using state-of-the-art diagnostics.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020197564.