At the Bordeaux University Hospital, among pregnant women aged less than 25 years-old the prevalence of C. trachomatis (CT) and N. gonorrhoeae (NG) is 12.5% and 2.4%, respectively for those requesting abortion by using the Abbott m2000 CT/NG test, and 7.9% and 0%, respectively, for those consulting for monitoring pregnancy by using the Roche Cobas 4800 CT/NG test.

The objective of this study was to evaluate and compare the performances of both of these tests along with a third one, the Cepheid GeneXpert CT/NG, for the detection of CT and NG in vaginal swabs collected from pregnant women consulting for abortion or for monitoring pregnancy. A patient was considered infected if at least two tests were positive.

Among 304 pregnant women included, from September 2012 to January 2013, 34 were infected, leading a prevalence of 11.7% (26/222) for patients requesting abortion and 9.7% (8/82) for patients consulting for monitoring pregnancy. There were two false CT-positive results with the Abbott m2000, one false negative result reported by Roche and the Cepheid GeneXpert. The sensitivity and specificity were 97% and 100% for the Roche and the Cepheid GeneXpert tests, and 100% and 99.3% for the Abbott assay. The positive predictive value ranged from 94.4% to 100% according to the test.

For NG, 297 specimens were negative and 7 were positive using the three tests. All results were concordant, leading to a sensitivity and specificity of 100% for all the assays. The prevalence of NG among pregnant women requesting abortion was 2.7% (6/222) and 1.2% (1/82) for those consulting for monitoring pregnancy.

In the populations studied, all three assays have similar performances for CT/NG detection.