Bacterial vaginosis in preterm labor

Adverse pregnancy and birth outcomes associated with Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum: a systematic review and meta-analysis

OBJECTIVES

Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum (genital mycoplasmas) commonly colonise the urogenital tract in pregnant women. This systematic review aims to investigate their role in adverse pregnancy and birth outcomes, alone or in combination with bacterial vaginosis (BV).

METHODS

We searched Embase, Medline and CINAHL databases from January 1971 to February 2021. Eligible studies tested for any of the three genital mycoplasmas during pregnancy and reported on the primary outcome, preterm birth (PTB) and/or secondary outcomes low birth weight (LBW), premature rupture of membranes (PROM), spontaneous abortion (SA) and/or perinatal or neonatal death (PND).Two reviewers independently screened titles and abstracts, read potentially eligible full texts and extracted data. Two reviewers independently assessed risks of bias using published checklists. Random effects meta-analysis was used to estimate summary ORs (with 95% CIs and prediction intervals). Multivariable and stratified analyses were synthesised descriptively.

RESULTS

Of 57/1194 included studies, 39 were from high-income countries. In meta-analysis of unadjusted ORs, M. hominis was associated with PTB (OR 1.87, 95% CI 1.49 to 2.34), PROM, LBW and PND but not SA. U. urealyticum was associated with PTB (OR 1.84, 95% CI 1.34 to 2.55), PROM, LBW, SA and PND. U. parvum was associated with PTB (1.60, 95% CI 1.12 to 2.30), PROM and SA. Nine of 57 studies reported any multivariable analysis. In two studies, analyses stratified by BV status showed that M. hominis and U. parvum were more strongly associated with PTB in the presence than in the absence of BV. The most frequent source of bias was a failure to control for confounding.

CONCLUSIONS

The currently available literature does not allow conclusions about the role of mycoplasmas in adverse pregnancy and birth outcomes, alone or with coexisting BV. Future studies that consider genital mycoplasmas in the context of the vaginal microbiome are needed.

PROSPERO REGISTRATION NUMBER

CRD42016050962.

Relationship between histologic chorioamnionitis and genital tract cultures in pre term labour

The objective was to determine the relationship of histological chorioamnionitis (HCA) with genital tract cultures in preterm birth. Among two hundred women recruited for the study, 100 were taken as cases with gestational age between ≥28 and <37 weeks and 100 women with gestational age >37 weeks were taken as controls. Vaginal swabs were taken for culture sensitivity and vaginal smears were made for performing whiff test and heat dry gram stained smear was examined for growth of microorganisms. Histopathologic examination of the placenta was done after delivery. 49 cases and 26 controls had evidence of histological chorioamnionitis. A significant difference was observed in relation to the presence of E. coli, presence of clue cells, positive whiff test and occurrence of bacterial vaginosis in subjects with and without histological chorioamnionitis. Thus, we conclude that the presence of histological chorioamnionitis is closely related to the presence of pathogenic microorganisms in the cervicovaginal region.IMPACT STATEMENTWhat is already known on the subject? Histologic chorioamnionitis has been regarded to reflect amniotic fluid infection and there are studies showing an association between histologic chorioamnionitis, amniotic fluid, and subchorionic plate cultures. Nevertheless, studies of the correlation of the cervical swab cultures with intrauterine infection in preterm birth remain inconclusive.What do the results of this study add? Histologic chorioamnionitis is closely related to the presence of pathogenic microorganisms in the cervicovaginal region.What are the implications of these findings for clinical practice and/or further research? High vaginal swab cultures and gram staining of vaginal smear is useful in detecting antenatal patients who are at a higher risk for preterm labour. After detection, early intervention may be done to avoid preterm deliveries in these high-risk pregnancies.

Cervical length versus vaginal PH in the second trimester as preterm birth predictor

Objective:

To evaluate diagnostic value of vaginal pH and cervical length measurement in the second trimester of pregnancy as a preterm labor (PTL) predictor.

Methods:

During a prospective cohort study 438 uncomplicated singleton pregnant women between 18 and 24 weeks of gestation were assessed regarding vaginal PH and cervical length. Vaginal pH was measured using Ph-indicator strips and cervical length was determined using transvaginal ultrasound. The cut-off values for vaginal PH and cervical length were defined as 5 and <30 mm respectively.

Results:

Vaginal pH of 5 and above was found in 162/438 women (37%) while cervical length <30mm was found in 38/438 (8.7%). The incidence of PTL < 37 weeks was 87/438 (19.9%) while the incidence of early (PTL <34 weeks) was 51/438 (11.6%). Predictive value of higher vaginal PH was significantly more (31%) than vaginal PH<5 (13%) in predicting PTL. As a result, alkaline vaginal PH significantly increases the odds of preterm labor (OR=3.06). Shortened cervical length is better predictor of PTL than higher vaginal PH with positive predictive value of 71% and negative predictive value of 85%. Cervical length less than 30 mm nearly 14-fold increases odds of preterm birth (OR=13.9).

Conclusion:

Compared to alkaline vaginal PH, shortened cervical length has better value to predict PTL overall. However, regarding early or late PTL, vaginal PH is more accurate to predict late PTL, while cervical length measurement is more appropriate to predict early PTL (<34 weeks).

Bacterial vaginosis and biomarkers of oxidative stress in amniotic fluid

OBJECTIVE

In this study we tried to determine if the activities of the primary antioxidant enzymes are detectable in amniotic fluid and if they can be used as early biomarkers of complications in pregnancy connected with bacterial vaginosis.

METHODS

This was a prospective study in which amniotic fluid was taken between 16 and 19 weeks of gestation. 161 pregnant women were divided into two groups: study group--patients with the treated local infection and control group--healthy pregnant women. Levels of reduced glutathione, and the activities of glutathione peroxidase, glutathione reductase, glutathione S-transferase, xanthine oxidase, superoxide dismutase and lipid peroxidation were determined spectrophotometrically in amniotic fluid samples.

RESULTS

Concentration of malonyldialdehide (product of lipid peroxidation) varied greatly between investigated groups. Xanthine oxidase and superoxide dismutase activities, though very low, were present in amniotic fluid samples. Also, enzymes of glutathione cycle and reduced glutathione concentrations were detectable and showed certain variations.

CONCLUSION

Although, biomarkers of antioxidant activity are present in the amniotic fluid, they are not different between women with and without bacterial vaginosis.