For the best odds of a pregnancy occurring sex needs to occur during the ‘fertile window’ of the menstrual cycle. The fertile window refers to the period of time up to 6 days before when the egg is released from the ovary (ovulation). Having sex during this time and particularly in the three days before ovulation and on the day of ovulation increases the likelihood that a pregnancy will occur.
To calculate the day when ovulation occurs however can be tricky as ovulation occurs 14 days before a period starts and requires knowledge of your cycle. Many women find it helpful to track their periods in order to determine if they are having intercourse in their fertile window. A Fertility calendar in the form of a paper chart like we have provided can be helpful for this as can the use of a smartphone app, many of which are available for free.
For women with irregular cycles, calculating the fertile window can be more difficult and makes timing intercourse more difficult. One solution for these women is to have sex every two to three days to avoid missing the window. Alternatively, cycle tracking via blood tests under the guidance of a fertility specialist or endocrinologist also ensures that the window is not missed.