How To Calculate Safe Period To Avoid Pregnancy?

Many people would consider calculating safe periods to avoid pregnancy. You can calculate safe days with high accuracy once you completely understand the menstrual cycle. Let us understand what is a safe period and how to calculate safe days to prevent pregnancy.

What Is A Safe Period?

Medical definition of the safe period is a portion of the menstrual cycle, and the days include immediately before and after the periods, usually when the chances of conception are less likely to occur.

During this unfertile period, the egg is not to be present to be fertilized. You can not get pregnant when the egg is not present as it is the unfertile period or safe period in a menstrual cycle.

Also Read: Pregnancy Symptoms After Missed Period

Why Calculate Safe Period?

Calculating the safe period or infertile period is one of the best birth control methods and helps in preventing unplanned pregnancies. It is important to calculate safe days if you do not wish to have a child immediately.

How To Calculate Safe Period To Avoid Pregnancy?

You need to understand different phases of the menstrual cycle to calculate the safe period or infertile period.

1. Menstruation:

It is nothing but the removal of the thick line of the uterus through the vagina. The menstrual fluid contains blood. Usually, the average period of menstruation is between three to seven days.

Also Read: Pregnancy Symptoms Before Missed Period

2. Follicular phase:

This phase starts from the first day of menstruation and ends with the ovulation period. In this phase, follicles maturation takes place.

3. Ovulation Phase:

This phase is nothing but the release of the mature egg from the surface of the ovary. This phase happens around two weeks of menstruation.

4. Luteal Phase:

The eggs burst during the ovulation phase. The ruptured follicles stay on the surface of the ovaries and the follicles transform into a structure called the corpus luteum. This starts releasing estrogen and progesterone. This forms a thickened lining of the uterus, waiting for the fertilized egg to stick, which is nothing but implantation.

Also Read: How To Get Pregnant With Twins?

If the fertilized eggs implant, it produces the hormones that are required to maintain the corpus luteum. This includes the HCG hormone that is detected in urine tests. This corpus luteum keeps producing progesterone, which is required to maintain the thickened lining of the uterus. If pregnancy does not occur, the corpus luteum dies around the 22nd day of the menstruation period. The drop in progesterone causes the lining of the uterus and this is the menstruation phase. This cycle repeats.

The safe period for a woman depends on the lifespan of the egg. Usually, ovulation occurs on the fourteenth day of the menstrual cycle. But it is varied from woman to woman. It can happen from around the 12th day to the 19th day. Chances to become pregnant if the unprotected sex is five days before the ovulation phase. Egg lifespan is 24 hours. If the fertilization does not happen within that time, the egg will die.

Also Read: Symptoms Of Baby Boy During Pregnancy

When To Have Sex To Avoid Pregnancy?

Usually ovulation period in a woman is around the 14th day and it can be possible in some women around the 12th day to the 19th day. If the sex is avoided during this ovulation phase is safe to avoid pregnancy.

The unfertile period and the ovulation phase are related as the safe days are calculated based on the ovulation. As per some popular safe period calculators, there are safe days to prevent pregnancy. Usually from day 1 to day 7 are safe days. And the fertilization can occur until the 20th day, this period is the time to avoid sex. But these calculations are approximate. The results may vary from woman to woman. Following the birth control methods help you better in preventing pregnancy.

Also Read: Symptoms Of Baby Girl During Pregnancy

Methods To Help Calculate Safe Period:

Here are the ways to help you calculate the safe days to avoid pregnancy.

1. Tracking Fertile Window:

Tracking your fertile window may help you determine your fertility period and prevent unwanted pregnancy. But his method works only if your periods are regular and uniform.
Here are the steps to track your fertile window:

  • Note down the first day, which means the day you begin bleeding, and count the total days until your next period starts. Do the same for six months continuously.
  • Note down the longest days and shortest days in these six months of menstrual cycle days.
  • Based on the average menstrual cycle days, you can calculate your fertile window.
  • Subtract eighteen days from the shortest menstrual cycle days. For eg, if the shortest cycle day is 25, and if you subtract 18 from it, then it will be seven. So, day 7 is the first fertile day.
  • Next, subtract eleven days from the longest menstrual days. For eg, if the longest cycle day is 33, and if you subtract 11 from it, then it will be 22. So, day 22 is the last fertile day.
  • So, from this, Day 7 to Day 22 is the best time to avoid sex.

Also Read: Foods To Avoid During Pregnancy

2. FAMs(Fertility Awareness Based Methods:

Fertility Awareness is also called the natural family planning method. This method is nothing but to predict the safe period and unsafe period for intercourse. These methods are to alert you on your ovulation period. Let us see the different fertility awareness methods and how they work.

A. Basal Body Temperature Method:

The basal body temperature is low in the initial days of your menstrual cycle. It starts rising slightly when it starts ovulating. For this, you will need a basal temperature thermometer. Using this special thermometer, the temperature will show a 0.5 to 1 degrees F increase after ovulation.

B. Cervical Mucus Method:

The hormones, which control your menstrual cycle, stimulate the cervix to produce mucus in the cervix and vagina. If the mucus is very clear and slippery than the mucus on other days, then you are more fertile.

C. Ovulation Predictors:

There are kits available to test and these can help you predict the ovulation period. But these are not that accurate.
Using these FAMs, the failure rate is high in predicting the safe period.
To calculate the safe period, first, you will have to understand ovulation and your menstrual period. Consulting the doctor is the ideal solution than following any other method. Did you try any other method after consulting your doctor to calculate your safe days? Do let us know your experiences in the comment box below.


The calendar method can be a helpful tool to increase awareness of your fertile window, but it’s not a foolproof way to avoid pregnancy. Due to variations in menstrual cycles and sperm viability, there’s always a chance of conception, even during your calculated “safe” days.

Here are some key takeaways:

  • Consider the calendar method as a supplementary strategy, not the sole method of birth control.
  • If you’re truly looking to avoid pregnancy, discuss reliable birth control methods with your doctor. They can advise you on options that best suit your needs and lifestyle.
  • Track your cycles diligently for a few months to get a better understanding of your personal fertility patterns.

Remember, your health and safety are important. If you’re unsure about your fertile window or have any concerns, consult a healthcare professional. They can provide personalized guidance and answer any questions you may have.


Leave a Reply

Your email address will not be published. Required fields are marked *