Early pregnancy threshold vaginal pH and Gram stain scores predictive of subsequent preterm birth in asymptomatic women

John C. Hauth, Cora MacPherson, J. Christopher Carey, Mark A. Klebanoff, Sharon L. Hillier, J. M. Ernest, Kenneth J. Leveno, Ronald Wapner, Michael Varner, Wayne Trout, Atef Moawad, Baha Sibai

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64 Scopus citations

Abstract

OBJECTIVE: The study was undertaken to identify early pregnancy vaginal markers predictive of subsequent preterm birth. STUDY DESIGN: In a multicenter Bacterial Vaginosis (BV) Trial, 21,554 women were screened with a vaginal pH and of these, two populations were studied. These included 12,041 who had a pregnancy outcome in the database and 6838 women who had a vaginal pH of 4.5 or greater and a Gram stain score and a pregnancy outcome in the database. ColorpHast Indicator Strips were used to determine the vaginal pH and the Nugent criteria were used to determine a vaginal Gram stain score of 0 to 10. RESULTS: Delivery at <37, <35, or <32 weeks' gestation was similar for women with a vaginal pH of less than 4.4 or 4,7 (P not significant) but was increased in women with a pH of 5.0 (P = .04, .02, .03, respectively) or with a pH of 5.0 or greater (at each gestational age P < .0001). The effect of pH of 5.0 or greater was similar for women who had a spontaneous preterm birth at each gestational age (P < .0001) or birth weight of less than 2500 g or less than 1500 g (P < .0005). Women with a vaginal pH of 4.5 or greater and a Gram stain score of 9 to 10 (compared with 0-8) had increased preterm births at <37, <35, and <32 weeks' gestation (P < .01), and birth weights less than 2500 g (P < .0001) or less than 1500 g (P < .01). Women whose vaginal pH was 5.0 or greater had a higher prevalence of vaginal fetal fibronectin ≥50 ng/mL (P < .0001), but the proportion of women with a vaginal fetal fibronectin ≥50 mg/mL did not differ by Gram stain score. CONCLUSION: Women with a vaginal pH of 5.0 or greater or a vaginal pH of 4.5 or greater and a Gram stain score of 9 to 10 had significantly increased preterm births at <37, <35, and 32 weeks' gestation and/or a birth weight less than 2500 g or less than 1500 g.

Original languageEnglish (US)
Pages (from-to)831-835
Number of pages5
JournalAmerican journal of obstetrics and gynecology
Volume188
Issue number3
DOIs
StatePublished - Mar 1 2003

Keywords

  • Early pregnancy vaginal pH/Gram stain
  • Preterm birth

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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    Hauth, J. C., MacPherson, C., Carey, J. C., Klebanoff, M. A., Hillier, S. L., Ernest, J. M., Leveno, K. J., Wapner, R., Varner, M., Trout, W., Moawad, A., & Sibai, B. (2003). Early pregnancy threshold vaginal pH and Gram stain scores predictive of subsequent preterm birth in asymptomatic women. American journal of obstetrics and gynecology, 188(3), 831-835. https://doi.org/10.1067/mob.2003.184