Halachically, medically, and in terms of staining, use of the NuvaRing is comparable to use of the pill. Its main advantage is that one is much less likely to forget to take it.
The ring should be removed prior to mikveh immersion. Some authorities also recommend removing it in order to perform the hefsek taharah and one bedikah on day one and day seven of the shivah neki'im. According to the manufacturer the ring can be out for up to three hours without affecting its efficacy. Therefore, this does not present a medical problem. For other bedikot, it can be removed or pushed to the side as you go round it.
With the pill about 10-15% of women do have some staining as their body gets used to the new hormonal milieu. Most improve by the second month of use. In theory, there could be less staining on the ring, as the ring gives a steady dose of the medication – in contrast to the peaks and ebbs with oral medication. Consult with your physician on this point. When you try any new method, you should be prepared to give it about three cycles before switching to another one.
You may also wish to review our article on staining as well as a question posted on the site which discusses this method.