How to Calculate Safe Period to Avoid Pregnancy?

With the increasing problems of weight gain, depression, headaches, nausea and intermenstrual spotting, more and more women are refraining from the use of birth control pills and relying on natural contraceptive methods to avoid unwanted pregnancy.

Fertility Awareness Method (FAM) is one of the most effectible natural methods to avoid pregnancy as well as determine the most fertile time of the month when you are likely to get pregnant.

Fertility Awareness is a collection of procedures which helps you to understand the natural functioning of your body so that you can calculate the safe period to avoid pregnancy.

Fertility awareness does not make use of any drugs, artificial barriers or devices. Instead it combines the Calendar method, Basal body temperature method and Cervical mucus method all together.

The Fertility Awareness Method is based in a few assumptions –

• An egg can live inside a woman’s body for 12 to 24 hours. But, it is best to consider 48 hours of time incase more than one egg is released.
• Sperm can live inside a woman’s body for 5 days after intercourse. So, pregnancy is most likely to occur if intercourse occurs anywhere from 3 days before ovulation to 2 to 3 days after ovulation.
• The exact time of ovulation is difficult to predict. So, it is best to add 2 or 3 days to the beginning and end of this fertility window. So, a woman’s fertile window or unsafe days are about 1/3rd of her cycle.

How to Calculate the Safe Days in a Menstrual Cycle?

A menstrual cycle lasts for 28 days on an average. The whole cycle is calculated from the first day of the period to the first day of the next period. So, safe period in one cycle is from Day 1 to 7 and day 21 to the rest of the cycle. During this period, a woman can have unprotected sex with her partner without getting pregnant. But, the safe period is not same for all women because in some women the menstrual cycle is less than 28 days, while in others it is longer than 28 days.

Understanding the Different Stages of a Woman’s Menstrual Cycle

It is important to have a thorough understanding of the different stages of the menstrual cycle in order to calculate the safe days and avoid pregnancy.

Pre-ovulatory phase – The pre-ovulatory phase or follicular phase is the first phase of the menstrual cycle that lasts from day 2 to day 14. During this stage the body releases the hormones that stimulate the egg to grow in the ovaries. The hormones also thicken the walls of the uterus so that it can receive the fertilized egg.

Ovulation phase – This is the second phase of the menstrual cycle where the ovarian follicle open up ad releases the mature egg that is supposed to be fertilized by the sperm. It is the most fertile phase of the cycle where the woman has highest chance of getting pregnant.

Post Ovulatory phase – The post-ovulatory phase or luteal phase is the last phase of the menstrual cycle which either ends in pregnancy or with the initiation of menstrual bleeding. During this phase the uterine lining becomes thicker and it lasts for 10 to 16 days.

5 Effective Methods to Calculate Safe Period to Avoid Pregnancy

Calendar Tracking Method/ Rhythm Method – Tracking your menstrual cycle on a calendar for several months can help to predict your fertile and infertile periods. Most women with regular period cycle can use this method to calculate the safe period.

1. Calendar Tracking Method

• Decide to track your menstrual cycle on a calendar for 8 to 12 months.
• The day your menstruation starts should be marked as Day 1.
• Go on tracking the menstrual cycle for 8 to 12 months and then pick the longest and shortest of the cycles from the tracking of the past 12 months.
• Determine the first day of your fertility window by subtracting 18 days from the length of your shortest period. For example – If your shortest cycle was 26 days, then subtract 18 from 26 (26-18=8) which comes to 8. Therefore, first day of your fertility window is on the 8th day of your cycle.
• Determine the last day of your fertility window by subtracting 11 from the length of your longest cycle. For example – If your longest cycle was 32 days, then subtract 11 from 32 (32-11=21), which comes to 21. Therefore, the last day of your fertility period is the 21st day of your cycle.
• So, the time in between, for example 8th day to 21st day of your cycle is known as the fertility window.

Ovulation is expected to happen during this period and if you are trying to avoid pregnancy then you should abstain from sexual intercourse of use a barrier form of birth control during the fertility window.

Effectiveness of Calendar Method

• Calendar method only predicts the most likely fertile days but it is not entirely reliable because the cycles keep varying in length due to various factors.
• Calendar method should always be used in combination with outer methods to ensure safety.
• This method is not useful if you experience irregular periods.

Basal body temperature method – Basal body temperature (BBT) is the lowest body temperature in a 24-hour period. You can get an accurate reading of your basal body temperature if you record it when you first wake up in the morning. Due to hormonal changes, a woman’s basal body temperature goes up right after ovulation. By tracking the BBT every morning for several cycles, a woman can determine the exact period in the cycle when she ovulates.

2. Basal Body Temperature Method

• The first step is to buy a basal thermometer. It is a special type of thermometer that extremely sensitive and records even minute changes in body temperature.
• Wake up at the same time every morning and check your temperature before getting out of bed.
• Basal body temperature can be taken in your mouth or your vagina. Taking the temperature in the vagina gives most accurate reading.
• After your take your temperature, write it down on a chart or diary. Record the date along with the temperature.
• Before your ovulate, your average body temperature should range between 97.2 and 97.7 degree F. 2 to 3 days after ovulation, your basal body temperature will rise between 0.4 to 1.0 degrees. The rise in temperature may last for 7 to 12 days before is drops back to a lower temperature.
• Over the months, you will observe a pattern in your temperature readings. There may be a gradual or sudden increase in temperature. This pattern will help you to anticipate your next ovulation period.
• Continue to track your basal body temperature every day for at least 3 months. After 3 months of tracking, you will be able to anticipate the time when you ovulate every month.
• Look at the charts and find a day when your temperature spike occurs each month.
• On a calendar, mark a day or two before this temperature spike as the day when you are most likely to ovulate. You should mark the date a day or two early because temperature spike occurs 2 to 3 days after ovulation.
• Avoid unprotected sex for at least 5 days before ovulation is supposed to start and through the ovulation day.

Effectiveness of Basal Body Temperature Method

• Basal body temperature method is good at predicting the ovulation period, but it cannot give you the precise date.
• Because temperature rise does not occurs until 2 or 3 days after ovulation occurs, so you need to make sure that no sperm is present in your body to fertilize the egg once it is released.
• Basal body temperature work more effectively when it is combined with other fertility awareness methods.

Ovulation Method/Cervical Mucus Method – The texture, color and smell of the cervical mucus continues to change throughout a woman’s menstrual cycle. Tracking the thickness, color and texture of your cervical mucus on a daily basis can help to monitor your fertility. You should refrain from unprotected sex once you notice any change in your mucus.

3. Ovulation/Cervical Mucus Method

• During the 5 days of menstruation the bleeding covers the mucus, so it is not possible to study the mucus.
• After completion of menstrual bleeding there is no mucus production for 3 to 4 days. This period is known as the “Dry Days”. These days are considered safe.
• Mucus production gradually increases every day after the “Dry Days” as the eggs begin to mature. You will be able to notice traces of mucus at the vaginal opening. It will have a white or yellowish color and sticky texture.
• Mucus production will be maximum just before you ovulate and it looks clear like egg white with a slippery or stretchy texture. This type of mucus indicates the peak fertility days.
• Ovulation occurs within 1 to 2 days of the peak day f stretchy, egg white like mucus.
• Such slippery, egg-white like mucus will be secreted for about 4 to 5 days and then there will be a fall in mucus production, with a few dry days before the next period.
• To check your mucus, wash your hands and then insert two fingers into your vagina and move them to and fro.
• You can also use a cotton swab to take up the mucus, but you will need to touch it to examine the texture.
• Keep careful record of the pattern of your mucus along with the date.
• Dry days after completion of menstrual bleeding are considered safe. Safe days also resume after the highly slippery, egg-white like mucus decreases and becomes sticky again. The dry days just before initiation of the next period are also considered safe.
• You should avoid unprotected sex 2 or 3 days before the slippery mucus begins to secrete.

Effectiveness of Ovulation/Cervical Mucus Method

• Ovulation or Cervical Mucus Method is quite effective in predicting the ovulation period.
• Ovulation method can be used in combination with Basal body temperature method to make it more accurate.

Symptothermal Method – Symptothermal method is a combination of all the three methods. Combining all the three methods for tracking fertility makes the process more effective and accurate. The procedures used in Symptothermal method include mucus method, basal body temperature recording cervix changes breast tenderness, abdominal pain, spotting, etc. This method is more effective for women who have irregular mucus changes or inconsistent temperature patterns due to stress or illness.

4. Symptothermal Method

• Use a basal thermometer to identify the slightest changes in temperature every day.
• Check for the consistency of cervical mucus and record it with the date. Note the features – yellow white, clear or cloudy, thick, stick, stretchy, etc.
• Your cervix goes through subtle changes throughout your menstrual cycle. Check the position of your cervix occasionally.
• Also notice other symptoms such as mid-cycle cramping, breast tenderness mood swings.

Effectiveness of Symptothermal Method

• The Symptothermal method has an overall failure rate of 13 to 20%. This means only 1 to 7 couples experience unwanted pregnancy after following this method.
• For those who feel uncomfortable with touching their bodies, this method can be used without checking the cervical position, but in that case, the method will be less effective.

Standard Days Method – Standard days method is like the Calendar method in which you need to calculate the days of the menstrual cycle that are most fertile. If your menstrual cycle is 26 to 32 days long, then this method considers the 8th day to the 19th day as the most fertile days. You should abstain from unprotected sec during this period to avid pregnancy.

5. Standard Days Method

• Buy a CycleBeads to keep track of your cycle. It is a special type of string of beads of different colors. 33 colored beads and a movable rubber ring are stringed on a rubber band.
• The first bead is black, the second bead is red, the next six beads are brown, the next 12 beads are white and the last 13 beads are brown.
• Each bead represents a day of the menstrual cycle except the black one.
• The red bead represent the first day of the period. Put the rubber ring on the red bead on the first day of period. Move the ring from one bead to another with every passing day in the direction of the arrow.
• The brown beads stand for the safe days. During these days you can have unprotected intercourse.
• The white beads stand for unsafe days. You should refrain from unprotected intercourse during these days.

Effectiveness of Standard Days Method

• Research proves that when used correctly, Standard Days Method can have more than 95% effectiveness in avoiding pregnancy. Less than 5 in every 100 women become pregnant while using Standard Days Method.
• But this method works accurately only id your cycles are regular and they are never longer than 32 days or shorter than 26 days.

Fertility Awareness Methods can be successful for women who use it consistently and reliably. Fertility awareness methods are preferred by many couples because they don’t have any side effects, they are absolutely safe and low cost and they do not require any medical device or medication. But in order to make these methods successful, both the partners need to be involved in the process.