Since sperm can live up to 3 to 5 days in a woman’s reproductive tract, and the life span of the typical egg is only around 24 hours, the period one week prior and one week after the approximate day of ovulation is considered a fertile period. The ovulation day may vary for each woman, and can occur from days 12 to 19 of the cycle. The days apart from this are called the safe periods to have sex, where the fertilization does not take place.
How to Calculate the Safe Period
Calculating the safest period in the menstrual cycle is simple. Here are the steps to follow:
1. Know your last period first date.
2. Determine the longest and shortest menstrual cycles by observing your menstrual cycle for last 6 months.
3. The first week of a normal menstrual period lasting 26-32 days averagely are calculated as a safe period, when you consider the sperm cells 3 to 5 day life span in the female reproductive track. The postovulatory infertile period is calculated based on ovulation occurring on the 19th day. Therefore, fertilization can result until day 20 of the cycle, when taking into consideration the 24 hour life cycle of the egg. The results may vary from woman to woman since it is a calendar based method.
Who Can Use This Method
If you consider using a safe period calculation to calculate a safe period to have sex, then note that the failure rate is around 3-4% annually, so make sure you understand the risks. If in the last 6 months your average menstrual cycleis between days 26 to 32, this calculation method can be effective. However, you should also discuss alternative birth control methods with your health care provider.
Who Can’t Use This Method
For those women whose last 6 menstrual cycle averages do not fall within the 26 to 32 day time frame, they will not be able to use this calculation method. Furthermore, women who have recently had a child will needto wait until they have averaged 6 menstrual cycles after giving birth, to determine if they can use the calculator method to calculate a safe period to have sex. Take note that the calculator method is not recommended for teens or women who are premenopausal.