Effects of long-term use of nonoxynol-9 on vaginal flora.
OBJECTIVE
Products containing nonoxynol-9 have been used as spermicidal contraceptives for many years, but limited data have been published describing the long-term effects of nonoxynol-9 use on the vaginal microbial ecosystem. This longitudinal study was conducted to examine the effects of nonoxynol-9 on the vaginal ecology.


METHODS
Vaginal swabs were obtained from 235 women enrolled in a randomized clinical trial before initiation of use of 1 of 5 different formulations of nonoxynol-9 for contraception, and up to 3 more samples were gathered over 7 months of use. The swab samples were evaluated in a single laboratory. The prevalence of several constituents of the normal vaginal flora was evaluated. The associations between nonoxynol-9 dosage, formulation, average product use per week, and number of sex acts per week were calculated.


RESULTS
The changes in prevalence of vaginal microbes after nonoxynol-9 use were minimal for each of the different nonoxynol-9 formulations. However, when both nonoxynol-9 concentration and number of product uses are taken into account, nonoxynol-9 did have dose-dependant effects on the increased prevalence of anaerobic gram-negative rods (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.1-5.3), H2O2-negative lactobacilli (OR 2.0, 95% CI 1.0-4.1), and bacterial vaginosis (OR 2.3, 95% CI 1.1-4.7).


CONCLUSIONS
This study demonstrated that most nonoxynol-9 users experienced minimal disruptions in their vaginal ecology. There were no differences between the different formulations evaluated with respect to changes in vaginal microflora. However, independent of the nonoxynol-9 formulation, there was a dose-dependent effect with increased exposure to nonoxynol-9 on the risk of bacterial vaginosis and its associated flora.


METHODS
II-2.
Schreiber
Courtney A
CA
Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine and Magee-Womens Research Institute, Pittsburgh, Pennsylvania, USA. corischreiber@yahoo.com
Meyn
Leslie A
LA
Creinin
Mitchell D
MD
Barnhart
Kurt T
KT
Hillier
Sharon L
SL
D000282:Administration, Intravaginal; D000328:Adult; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D015999:Multivariate Analysis; D017137:Nonoxynol / Q000009:adverse effects / Q000494:pharmacology*; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D013089:Spermatocidal Agents / Q000009:adverse effects / Q000494:pharmacology*; D014621:Vagina / Q000187:drug effects*; D014622:Vaginal Creams, Foams, and Jellies / Q000494:pharmacology; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000209:etiology
D013089:Spermatocidal Agents; D014622:Vaginal Creams, Foams, and Jellies; D017137:Nonoxynol