Find out more about the possibilities of pharmaceutical marketing: http://www.cast-pharma.com/pharma-biotech-marketing-solutions/?ref=yt Connect with me on LinkedIn: http://www.linkedin.com/pub/stefan-wolf/6/31b/648 The fertile window is not easy to determine exactly, even if the length of the menstrual cycle is regular. This makes it difficult to pin-point the fertile days and assess the risk of becoming pregnant. As a consequence, it is always — during the entire cycle –absolutely necessary to use contraceptives in order to make sure sexual intercourse does not lead to unintended pregnancy. Please note that this video is for showcase purposes only. It does not inform nor does it attempt to explain the respective medical topic or mechanism of action in a comprehensive manner. CAST PHARMA is not responsible for the medical content of this film. ©CAST PHARMA