The most fertile days of a woman's menstrual cycle are when she is ovulating, generally between days 11 and 14, though it varies between women, according to MedlinePlus. Since ovulation varies, doctors recommend that couples try to conceive between days seven and 20 of the menstrual cycle.
If women do not have a regular menstrual cycle, there are several ways to predict ovulation, including by purchasing an over-the-counter ovulation kit, explains MedlinePlus. Evaluating the cervical fluid and taking the basal body temperature may also help to predict ovulation.
The cervical fluid serves as a protector of the sperm, and it helps the sperm move into the uterus, states MedlinePlus. During ovulation, the cervical fluid changes, and by paying attention to the changes, a woman knows if she is ovulating. When ovulating, the fluid first becomes sticky and then takes on a whitish color. When the woman is very fertile, the fluid becomes stretchy, slippery and clear, similar to an egg white.
Taking the basal body temperature can also help a woman know when she is fertile, claims MedlinePlus. During ovulation, the body temperature rises about one degree and stays high until ovulation is over. A woman can use a special thermometer to take her temperature as soon as waking in the morning and recording this over time. When it goes up, ovulation is occurring.