Gram-stain diagnosis of bacterial vaginosis after rupture of membranes

Correlation of the Cram stains prior to and after rupture of the membranes (ROM) and the efficacy of Gram-stain diagnosis for bacterial vaginosis (BV) after membrane rupture has not previously been evaluated. From April 1997 to May 1998, women presenting in labor or for labor induction were invited to participate. Women with ROM prior to hospital presentation or contraindi cations for vaginal delivery were excluded. A Gram stain of vaginal secreti ons was obtained prior to and approximately 2 hours after ROM. BV was diagn osed with a Nugent score of 7-10. The Gram stain prior to and after membran e rupture was evaluated using the Spearman correlation coefficient. Populat ion characteristics (n = 91) included maternal age of 15 to 38 years, 45 (4 9%) nulliparas, 59 (65%) African-Americans, 23 (25%) Hispanics, 7 (8%) Cauc asian, and 2 (2%) Asians. Gestational age upon study entry was 35 to 44 wee ks. Twenty-one percent (19 of 91) of the study population was diagnosed wit h BV. Using the Gram stain prior to membrane rupture as the standard, the e fficacy of the Gram stain after ROM had a sensitivity of 26%, specificity o f 97%, positive predictive value of 71%, and negative predicative value of 83%. Good correlation of pre- and post-membrane rupture Cram stains was dem onstrated (r= 0.69). Cram stain may be useful for ruling out BV in the pres ence of membrane rupture, but is not useful for diagnosing BV due to poor s ensitivity.