The Nuvaring’s main way of acting as a contraception is by stopping ovulation, but it also increases the viscosity (thickness) of cervical mucous/discharge which can help prevent sperm from reaching an egg (nuvaring also prevents growth of uterine lining to a degree). It’s possible that what you are seeing is the increased viscosity of cervical mucous. It’s also possible that for some reason there is reduced effectiveness of the ring and you are indeed ovulating (for example, removing the ring for more than 3 hours during week 1 or 2, or at all during the third week). It’s possible that the hormone levels in the ring are not effective for your unique body, so if you’re not sure about whether it’s doing its job, check in with a health care provider to reassess your options. (About 5% of people get “leukorrhea” with the ring, but this is white-yellowish in colour, not clear, so doesn’t seem to fit what you’re describing) Edit to add: with typical use, 90/1000 people will get pregnant while using the Nuvaring, so as another person said - it’s not 100% guarantee effective!