Question: I just switched from the patch to NuvaRing. I have problems with recurrent yeast infections. To maintain vaginal pH, I have used intra-vaginal medications Fem PH or Relagard. Is it okay to use this medication with the NuvaRing or are the acids in it damaging to the ring?
Answer: NuvaRings are not affected by the vaginal meds you are currently using.
From the chapter on NuvaRings in Contraceptive Technology:
Vaginal symptoms. In clinical trials, the most common reason for discontinuation was vaginal symptoms or problems related to ring use, such as ring expulsion, foreign body sensation or coital problems, occurring in 1-2.6% of women. Other self-reported vaginal symptoms include vaginitis, leukorrhea, and vaginal discomfort. In a recent randomized comparative trial, however, the only vaginal symptom significantly associated with NuvaRing use was vaginal wetness; 63% of ring-users reported vaginal wetness compared with 43% of COC users. Microbiological evaluation showed ring use to be associated only with an increase in hydrogen peroxide producing Lactobacillus.
Vaginal symptoms
Advise women that they may perceive more vaginal discharge or wetness while using the ring, but that this does not signify infection. Counsel them that there is no increased risk of vaginal infection with    NuvaRing use. However, if a woman complains of vulvovaginal itching or a foul odor, she should be evaluated and treated as needed.
Low steady release of hormones: The ring has a steady release rate, providing a low and consistent release of hormones. Although the ring users have progestin levels similar to those of COC users, their EE levels are lower: two-fold lower than those in women taking 35 µmg EE COCs and three-fold lower than those in women wearing the patch. One recent study found that, in the first 3 months of use, fewer patients called about side effects from the NuvaRing than they did about the patch or COCs. Pharmacokinetic parameters are only surrogate endpoints, however, and may not necessarily reflect a decreased risk of estrogen-related side-effects or long-term risks.
Excellent cycle control: Compared with COCs, the ring is less likely to produce irregular bleeding, especially in the first few cycles. Most vaginal ring users experience withdrawal bleeding on schedule.
