Risk of bacterial vaginosis, Trichomonas vaginalis and Candida albicans infection among new users of combined hormonal contraception vs LNG-IUS.

OBJECTIVE

The study assessed the risk of bacterial vaginosis, Trichomonas vaginalis and Candida albicans infection among new users of either a combined oral contraceptive pill (COC) or the levonorgestrel-releasing intrauterine system (LNG-IUS).

METHODS

This prospective observational study included 430 women, without active vaginitis at inclusion, who were divided into two groups according to their chosen method of contraception: COC group (n = 236) and LNG-IUS group (n = 194). Participants were examined for bacterial vaginosis, T. vaginalis and C. albicans infection initially and then at 6 weeks, 6 months and 12 months after the start of contraceptive use. Data were collected and statistically analysed.

RESULTS

The rates of acquisition of bacterial vaginosis, T. vaginalis and C. albicans infection during follow-up were significantly increased and comparable between the groups (p < .001) and decreased in frequency over time (p < .05). The rates of acquisition of bacterial vaginosis among COC users (Nugent score) were 24.6, 18.6 and 15.2% and among LNG-IUS users 20.6, 13.5 and 9.3% at 6 weeks, 6 months and 12 months, respectively (p < .001). Body mass index >25 kg/m2, history of bacterial vaginosis, history of sexually transmitted infection, vaginal douching more than five times per week and coital frequency more than five times per week were strong risk factors for acquisition of bacterial vaginosis during the follow-up period (p < .001).

CONCLUSIONS

The use of COCs and LNG-IUS is associated with an increased, comparable risk of acquisition of bacterial vaginosis, T. vaginalis and C. albicans infections, which is greatest during initial use of the method but which improves over time.