Adverse pregnancy and perinatal outcomes associated with Mycoplasma genitalium: systematic review and meta-analysis

Objective To examine associations between Mycoplasma genitalium infection during pregnancy and adverse outcomes. Methods We did a systematic review of observational studies. We searched Medline, EMBASE, the Cochrane Library and CINAHL up to 11 August 2021. Studies were included if they compared preterm birth, spontaneous abortion, premature rupture of membranes, low birth weight or perinatal death between women with and without M. genitalium. Two reviewers independently assessed articles for inclusion and extracted data. We used random-effects meta-analysis to estimate summary ORs and adjusted ORs, with 95% CIs, where appropriate. Risk of bias was assessed using established checklists. Results We identified 116 records and included 10 studies. Women with M. genitalium were more likely to experience preterm birth in univariable analyses (summary unadjusted OR 1.91, 95% CI 1.29 to 2.81, I2=0%, 7 studies). The combined adjusted OR was 2.34 (95% CI 1.17 to 4.71, I2=0%, 2 studies). For spontaneous abortion, the summary unadjusted OR was 1.00 (95% CI 0.53 to 1.89, I2=0%, 6 studies). The adjusted OR in one case–control study was 0.9 (95% CI 0.2 to 3.8). Unadjusted ORs for premature rupture of membranes were 7.62 (95% CI 0.40 to 145.86, 1 study) and for low birth weight 1.07 (95% CI 0.02 to 10.39, 1 study). For perinatal death, the unadjusted OR was 1.07 (95% CI 0.49 to 2.36) in one case–control and 38.42 (95% CI 1.45 to 1021.43) in one cohort study. These two ORs were not combined, owing to heterogeneity. The greatest risk of bias was the failure in most studies to control for confounding. Conclusion M. genitalium might be associated with an increased risk of preterm birth. Further prospective studies, with adequate control for confounding, are needed to understand the role of M. genitalium in adverse pregnancy outcomes. There is insufficient evidence to indicate routine testing and treatment of asymptomatic M. genitalium in pregnancy. PROSPERO registration number CRD42016050962.


Methods, Information sources
Search strategy 7 Present the full search strategies for all databases, registers and websites, including any filters and limits used. Text S1 Selection process 8 Specify the methods used to decide whether a study met the inclusion criteria of the review, including how many reviewers screened each record and each report retrieved, whether they worked independently, and if applicable, details of automation tools used in the process.

Methods, Study selection; Text S2
Data collection process 9 Specify the methods used to collect data from reports, including how many reviewers collected data from each report, whether they worked independently, any processes for obtaining or confirming data from study investigators, and if applicable, details of automation tools used in the process.

Methods, Study selection and data extraction
Data items 10a List and define all outcomes for which data were sought. Specify whether all results that were compatible with each outcome domain in each study were sought (e.g. for all measures, time points, analyses), and if not, the methods used to decide which results to collect.
Methods, Study selection and data extraction; Protocol, Codebook S2 10b List and define all other variables for which data were sought (e.g. participant and intervention characteristics, funding sources). Describe any assumptions made about any missing or unclear information.
Protocol, Codebook S1 Study risk of bias assessment 11 Specify the methods used to assess risk of bias in the included studies, including details of the tool(s) used, how many reviewers assessed each study and whether they worked independently, and if applicable, details of automation tools used in the process.

Methods, Risk of bias in individual studies
Effect measures 12 Specify for each outcome the effect measure(s) (e.g. risk ratio, mean difference) used in the synthesis or presentation of results. 13a Describe the processes used to decide which studies were eligible for each synthesis (e.g. tabulating the study intervention characteristics and comparing against the planned groups for each synthesis (item #5)).

Methods, Data synthesis and analysis
13b Describe any methods required to prepare the data for presentation or synthesis, such as handling of missing summary statistics, or data conversions.

Methods, Data synthesis and analysis
13c Describe any methods used to tabulate or visually display results of individual studies and syntheses. Methods, Data synthesis and analysis 13d Describe any methods used to synthesize results and provide a rationale for the choice(s). If meta-analysis was performed, describe the model(s), method(s) to identify the presence and extent of statistical heterogeneity, and software package(s) used.

Methods, Data synthesis and analysis
13e Describe any methods used to explore possible causes of heterogeneity among study results (e.g. subgroup analysis, meta-regression).

Risk of bias across studies and certainty of the body of evidence
13f Describe any sensitivity analyses conducted to assess robustness of the synthesized results.

Risk of bias across studies and certainty of the body of evidence
Reporting bias assessment 14 Describe any methods used to assess risk of bias due to missing results in a synthesis (arising from reporting biases).

Risk of bias across studies and certainty of the body of evidence
Certainty assessment 15 Describe any methods used to assess certainty (or confidence) in the body of evidence for an outcome.

Risk of bias across studies and certainty of the body of evidence
Study selection 16a Describe the results of the search and selection process, from the number of records identified in the search to the number of studies included in the review, ideally using a flow diagram.
Results ,para 1-2, p. 6, Figure S1 16b Cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why they were excluded.

Not done
Study characteristics 17 Cite each included study and present its characteristics. Results, Table 1; Table S2 Risk of bias in studies 18 Present assessments of risk of bias for each included study. Tables S10 and S11

Results of individual studies
19 For all outcomes, present, for each study: (a) summary statistics for each group (where appropriate) and (b) an effect estimate and its precision (e.g. confidence/credible interval), ideally using structured tables or plots. Results, Table 2