Once -A special period tracker

Once -A special period tracker is a health & fitness app by (주)넵튠 with 1,000,000+ downloads (about 2.9M estimated). Rated 4.2 from 23K ratings. Released Jun 14, 2010. Install growth, rank history, SDKs and ad networks.

From the store listing: “For the all women who need menstruation recording calendar For the all women who need caring dairy for irregular menstrual pain and menstrual cycle For the all women who want to know the fertility, ovulation, contraception and probability of pregnancy through calendar For the all women who annoys marking menstruation…”