Fertility awareness based methods of contraception, lactational amenorrhoea and withdrawal

What Are Fertility Awareness Based Methods (FABMs) of Contraception?

Fertility Awareness Based Methods of contraception (sometimes called Natural Family Planning methods) are based on identifying the fertile days of the menstrual cycle in order to avoid a pregnancy.

How do FABMs work?

Sperm can survive in the uterus or fallopian tubes for up to 5 – 7 days but the released egg survives for only 12 – 24 hours. A woman is most fertile in the week before ovulation (egg release) until a day after ovulation has occurred.

FABMs involve:
• observing fertile signs such as cervical mucus secretions, cervical changes and basal body temperature (symptoms-based methods)
• monitoring the days of the menstrual cycle (calendar–based methods)

How effective are FABMs?

The effectiveness of these methods relies on the motivation to avoid a pregnancy and the type of method used. Advice from an expert educator is recommended (see information at the end of this fact sheet).

If used correctly every time these methods are 75 – 99% effective. This means that if 100 women used these methods, between 1 and 25 could become pregnant in a year. These methods are more effective the longer they are used.

Advantages as a method of contraception

• Cost effective
• Does not interfere with the menstrual cycle
• Women gain awareness of when they are most fertile and this can be used to prevent or achieve a pregnancy
• Can be used in combination with barrier methods during the ‘fertile’ days

Disadvantages as a method of contraception

• Requires daily awareness of physical changes and continual observation and recording of signs and symptoms of fertility in a cycle
• May require long periods of abstinence
• It can be difficult to confidently predict ovulation
• It can take between 3 – 6 cycles to accurately identify fertile days of a woman’s cycle
• Indicators of fertility can be changed by events such as illness, having sex and stress
• There is no protection against sexually transmissible infections (STIs).

Are FABMs suitable for all women?

Women who have a strong preference for fertility awareness based methods because of religious, cultural or health reasons may find these methods suit them best.

Partner cooperation is an important factor in the successful use of these methods.

Some situations can make fertility awareness based methods more difficult to manage, for example:
• after stopping hormonal methods of contraception
• women with irregular periods or approaching menopause could have difficulty in predicting fertile times

What are the different methods used?


Calendar-Based Methods

These include the calendar rhythm method and the standard days method, and involve calculating the fertile days using the dates of previous months’ cycles. This method is best used after charting at least three cycle lengths.
• The first day of a menstrual period is counted as day one of a cycle
• Cycle length is measured from the start of one period to the day before the start of the next
• After reviewing three cycle lengths the woman selects the shortest and longest cycles
• This method must be regularly reassessed, especially if the cycle lengths vary.

Calendar rhythm method
Select the shortest and longest cycle lengths, subtract 21 from the shortest cycle and subtract 10 from the longest cycle. For example, for a woman whose cycle varies between 26-30 days:
Shortest cycle: 26-21=5
Longest cycle: 30-10=20
Her fertile days are between days 5 and 20, and she should have no unprotected sex on those days.
In a regular cycle the calculation is the same. For example in a regular 28 day cycle the fertile days are days 7 to 18.

Standard days method
This is a simpler version of the calendar method and should not be used for a woman who has recorded two cycles outside the range of 26-32 days in any one year.
First fertile day is day 8; last fertile day is day 19.
There should be no unprotected sex between and including days 8 and 19.

Cyclebeads are a colour-coded system of beads based on this method. Further information can be found at www.cyclebeads.com.

Calendar-based methods alone are not very reliable, with 5 to 47 women falling pregnant out of 100 women in a year. It should be used in combination with other fertility awareness based methods.

Symptoms-Based Methods

Symptoms-based methods involve identifying one or more signs of fertility using the basal body temperature, cervical mucus secretions or cervical changes.

Temperature Method
The basal body temperature (BBT) is the lowest temperature taken on morning wakening. Following ovulation, rising levels of progesterone will raise the basal body temperature by between 0.2 - 0.5 degrees Celsius, which indicates ovulation is over. The temperature will remain elevated until the next period.
• The temperature must be taken at the same time every day
• The temperature can be taken either orally or vaginally but must be from the same place throughout the cycle
• The basal body temperature must be taken immediately after waking, before getting out of bed and before eating, drinking or any other activity
• The fertile time ends when there are three consecutive days of recorded temperatures that are higher than the preceding six days. After this it is considered safe to have unprotected sex

Things to consider:
• Accuracy: a digital thermometer is best
• Body temperature can be raised by a number of additional factors such as illness, alcohol, sleeping in later than usual, too little sleep, and electric blankets
• This method alone may require many days of abstinence

Cervical Mucus Method (Including Billings Ovulation Method)

This method involves the observation of the variations in cervical mucus secretions found at the vaginal opening. This can be used to identify fertile days because the hormone changes through a woman’s cycle affect the consistency of these secretions felt at the vaginal opening.

Mucus is divided into three distinct patterns:
1. Post menstrual infertile pattern: immediately after menstruation the vaginal opening feels dry, or with a dense, flaky mucus that has a sticky feel to it
2. Ovulatory or fertile pattern: rising oestrogen levels give a feeling of wetness at the vaginal opening. Mucus is becoming clear, more watery and elastic (a texture like raw egg white)
3. Post ovulatory infertile pattern: rising levels of progesterone cause the mucus to become cloudy, thicker and sticky and the vaginal opening once again feels dry
Sexual intercourse can resume safely after three consecutive ‘dry’ days.

Things to consider:

• Possibly treat any bleeding or spotting during the cycle as potential fertile days
• Sexual excitement, semen and menstrual blood can mimic or conceal the effects of fertile mucus, making mucus interpretation more difficult

Symptothermal Method

This method uses observation of a combination of two or more signs of fertility including temperature, cervical mucus secretions and changes in the cervix, to calculate fertile times of the cycle. By combining these methods, the accuracy of identifying the fertile time and therefore the effectiveness is increased.

How do I learn about these methods?

Those interested in developing a detailed understanding in the use of FABMs and requiring individual support are encouraged to contact local Natural Family Planning educators (www.naturalfertilityaustralia.org.au and www.natfamplan.com.au).


LAM is the use of breastfeeding as a contraceptive method. Breastfeeding has an effect on the production of hormones that reduces the probability of ovulation, which reduces the chance of pregnancy.

How effective is this method?

This method provides more than 98% protection from pregnancy if:
• menstrual periods have not returned since the birth
• the baby is fully breastfeeding day and night, not being fed supplements (still solely breastfeeding) and there are no long intervals between feeds (suggested as no more than 4 hours during the day, or 6 hours at night)
• it has been less than six months since the birth
The effectiveness of this method is reduced when the frequency of breastfeeding decreases.


Withdrawal is the method of contraception when a man removes (withdraws/pulls out) his penis from a woman’s vagina before he ejaculates (cums/comes).

How effective is withdrawal?

Very little research has been done into the effectiveness of this method.

As sperm can be present in pre-ejaculation fluid there is a risk of pregnancy even if the man withdraws before ejaculation. Other methods of contraception offer greater effectiveness. However, withdrawal can be an effective method of contraception particularly for experienced well-motivated users.

For further information

• Call the Family Planning NSW Talkline on 1300 658 886 or go to www.fpnsw.org.au/talkline
• NRS (for deaf) 133 677

The information in this Factsheet has been provided for educational purposes only. FPNSW has taken every care to ensure that the information is accurate and up-to-date at the time of publication. Individuals concerned about any personal reproductive or sexual health issue are encouraged to seek advice and assistance from their health care provider or visit a Family Planning clinic.


Fertility Awareness Based (FAB) methods of contraception (sometimes called Natural Family Planning methods) are based on identifying the fertile days of the menstrual cycle in order to avoid a pregnancy.

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