The temperature method itself is generally nothing new. The basal body temperature method is based on the fact that the body temperature rises during the menstrual cycle. The menstrual cycle lasts approximately 28 days and at the beginning there are several eggs waiting to develop. There are two hormones that are particularly important in the menstrual cycle, the first one is the follicle stimulating hormone and the other is the corpus luteum supportive hormone. When the FSH (follicle-stimulating-hormone) is high at the beginning of the cycle, the follicles will be selected, usually 10, 5 on each side, and from day 5 it will be clear which follicle will go on to develop into an egg. When the body temperature rises it means that the instruction to ovulate has begun. An egg will be released from the follicle and the corpus luteum is created in order to sustain a pregnancy. Then either an embryo implants and the period is missed or there is no implantation and menstruation begins. The rise in body temperature is determined by hormones, the hormone gives the instruction to ovulate, the progesterone rises and with it the body temperature. The difficulty with the basal body temperature method is that the temperature is only measured once a day. With the femSense patch it is different. femSense lets you know, based on previous cycles, when your next ovulation is predicted, Because the system is made up of a temperature sensor patch and an app, which has your cycle relevant information, the system can tell you when to apply the patch and when to activate it. The active patch can then communicate with your phone and measure your temperature thousands of times in 7 days. Through this continuous measurement all the problems with the old basal body temperature method are solved. The app and its algorithm recognizes when a woman went to bed late, it can accurately predict when ovulation is expected and a couple can use this information to plan a romantic evening to get pregnant.