Charting your cycles, examining cervical fluid, and measuring basal body temperature are the most efficient ways to predict your reproductive window. Ovulation test kits will help you anticipate ovulation more accurately. If you keep track of your cervical fluid, you'll notice that it becomes egg-white in consistency when you're going to ovulate. And your basal body temperature will rise just before ovulation. Other signs that you're fertile include increased sexual desire, fatiguelessness, and changes in bowel movement frequency or shape. The presence of these symptoms does not necessarily mean that you will get pregnant; only tracking your cycles effectively can do that for you. Your menstrual cycle has two parts: menstruation (or menses) and fertility. Your fertility period starts on the first day of your last menstrual period and ends on the first day of your next period. So if your periods are 28 days apart, you're fertile for 14 days at a time. Menstrual cycles are different for women who use contraception. With some methods of birth control, including the pill and intrauterine devices (IUDs), missing one period in three isn't unusual. With other forms of contraception, such as tubal ligation (tying off or removing both the fallopian tubes) or a subdermal implant, menopause may be imminent (within five years). Contraception is any action taken to prevent pregnancy.