Persona contraceptive kit. Close-up of Persona, a contraceptive kit for women based on hormone levels in morning urine. The kit works on the principle that hormone (oestrogen and progesterone) levels will be highest around the time of ovulation. This is the time that the risk of pregnancy is at its highest. Here, the test stick (long, grey) has just obtained a reading. The number (29) on the display indicates the day of the menstrual cycle. The green light indicates that it should be safe to have sexual intercourse without fear of pregnancy. (A red light would indicate that it was not safe). This kit could also aid couples planning a family.