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What are Natural Family Planning Methods?
Blog | What are Natural Family Planning Methods?

What are Natural Family Planning Methods?

Oct | 2016 | Team Foresight

Natural Family Planning (NFP) Methods – from the UK’s leading NFP expert, Coleen Norman

Natural Family Planning methods offer invaluable insight for individuals and couples experiencing fertility issues, breastfeeding mothers and for couples seeking non-invasive contraception.

The following was written by NFP expert Colleen Norman of Fertility Education and Training:


I would like to show how, by offering an education programme in fertility, I have seen couples, both fertile and sub-fertile, grow confident, happy and autonomous in their ability to control their fertility, empowered to plan, space and ultimately limit the births of their children, with no health risks or side effects incurred, using newly acquired knowledge and skills.  I would like to demonstrate from my experience that there is a great need for such education, and considerable benefit to be gained by both the doctor and the patient.

Fertility Facts

  1. A woman produces usually only one egg per cycle which is fertilisable for no more than 12 hours after release.
  2. That for about 6 days before ovulation, the cervix opens and produces a fertile mucus secretion which keeps sperm alive for 3-6 days, enabling them to survive inside the woman until the egg is released.
  3. That a woman is fertile due to this mucus for about 6 days before ovulation and only 2 days after, allowing for the release and life of the egg.
  4. That all the rest of the time she is infertile because the cervix is sealed with a sticky mucus plug which blocks the passage of sperm.

Mucus is produced from cell glands in the cervical crypts in response to hormonal changes (Billings et al.1972). It appears in two forms commonly referred to as ‘the mesh mucus’ and ‘the motorway mucus’ (Fig. 1). The mesh mucus traps the sperm and destroys them by acidity, whereas the alkaline motorway mucus just before ovulation entices, nourishes, energises and transports the sperm into the cervical crypts where they can survive for several days. Odeblad (1997) has shown there is also a filtration mechanism built into the fertile mucus for filtering out abnormal spermatozoa.

1-time-of-infertility              2-time-of-fertility

This is the clinician’s view of cervical mucus, but the woman translates it into her daily observations. For her, the mesh mucus is white and creamy, producing a dry feeling at the vulva, while the fertile, motorway mucus is clearer, has the texture of raw egg-white and produces a marked feeling of wetness and lubrication at the vulva. It is universal to all fertile women.


Figure 2: Hormones which cause changes

The hormones which cause the changes in cervical mucus are simply illustrated in Figure 2:

Myths of the Menstrual Cycle

Most literature limits ovulation to 14 days before menses, which presumes that every corpus luteum has a fixed predictable life of two weeks. In fact the corpus luteum survives from 10 to 16 days, with different women having their own individual pattern. This means that even in a group of women with regular 28 day cycles, there is a considerable individual variation in the time of ovulation, as shown in figure 3 below:

4-myths-of-menstral-cycleCounting the start of the period as Day 1 of a cycle, some may ovulate as early as Day 12 and menstruate 16 days later. Others have the text book cycle of “mid-cycle ovulation” on Day 14, while others may ovulate on Day 16 with a 12 day gap before the next period. The last group may ovulate as late as Day 18 with only a 10 day gap to menses. A short luteal phase on its own is no cause for anxiety because the woman is still fertile.

However, one can see that in the last example, a post-coital test done on day 13 will have unfavourable results, simply because it was done too early for the belated ovulation on day 18. Similarly, ovulation/LH test kits currently on the market often fail because they tell a woman with a 28 day cycle to begin testing on Day 11 and the limited number of test sticks are used up before the LH surge occurs probably around Day 17.

Coping with Irregular Cycles

Women with irregular cycles may be called in to a clinic for “Day 21” progesterone tests when they haven’t even ovulated, but this does not necessarily mean that they are not going to ovulate and are therefore capable of conception.

The Temperature Method

To overcome these problems, some clinics offer temperature charting. As Fig.4 below shows, progesterone, released after ovulation, raises body heat for 10-16 days. As the corpus luteum fades and progesterone levels fall, the temperature falls with onset of menstruation. When pregnancy is achieved, progesterone remains high and so does the temperature, for 9 months! To achieve good charts, rules must be understood and applied.

  1. Temperature must be taken in bed on waking, at about the same time each morning, after a reasonable night’s sleep.
  2. A mercury thermometer must be left in place for 5 minutes orally. Digital ones require less time.

False rises are caused by:

  • Alcohol the night before
  • Fever, migraines
  • Taking it at differing times

These disturbances must be recorded and the reading discounted, otherwise the chart becomes unreadable. An oversleep of two hours could look like an ovulation rise.


Figure 4: The Temperature Method

Since the temperature shift occurs up to 48 hours after ovulation, only the first two high readings are considered potentially fertile. After the third genuine high reading, Tietze showed that the pregnancy rate from intercourse in the remainder of the luteal phase is comparable only to female sterilisation.

The most fertile days

The most fertile days on the chart are the last 3 low temperatures before the shift, when the ‘motorway mucus’ is at its peak. Unless mucus observation is taught, how can a woman know which are her last three low readings in irregular cycles? The temperature rise confirms ovulation, but only retrospectively, and is therefore little help in the timing of intercourse in irregular cycles.

Success of mucus observation


Figure 5: Mucus Observation

The facts in favour of better fertility education speak for themselves. The World Health Organisation (WHO) Multi-Centre Trial showed that, after one teaching cycle, 93% of fertile women, could accurately identify the fertile mucus phase. After 3 teaching cycles, the figure rose to 97%.   Another study, in a French infertility clinic showed that out of 25 women brought in for ovulation tests based on calendar calculation, only 9 were actually successful on the first appointment. By contrast, out of 25 women, who were simply shown photos of fertile mucus and told to attend when they saw similar mucus, 20 women had successful tests on their first appointment – chosen by themselves.

Stress Factors to be considered

Some consultants argue that mucus observation and temperature charts add to a couple’s stress. Certainly, continuous temperature charting can be stressful, reminding the woman each day as she wakes up that she is still childless. Therefore, after the first two cycles, temperature charting is confined simply to the days around ovulation, as dictated by the mucus chart.

Mucus observation however, empowers a couple to help themselves. It can be done at any time during the day and is discontinued once ovulation is over. Like temperature charting, it is kept to the minimum time around ovulation.

Mucus Testing from a Woman’s Perspective

Many doctors see it only as a laboratory test and this is a misunderstanding. It is not the sole right of the clinician to conduct the “spinbarkheit test.” A woman wiping the vulva and stretching the mucus between her fingers or toilet tissue is conducting the same scientific test. She may not see the swimming lanes that the microscope reveals, but she understands from its raw egg-white nature that ovulation is imminent. The peak mucus symptom has been shown to have the same accuracy in detecting ovulation as ultrasound and LH peak, yet costs nothing. (J. Depares et Al).

Far from creating stress, I have found couples more motivated by a sense of greater control and personal empowerment, being able to ensure tests were carried out at the right time, able to time intercourse more accurately and no longer subject to false hope of pregnancy from a belated menses caused by a late ovulation. I have charts of conception cycles from women who conceived on day 40 of their cycle and later, who said that, but for the mucus symptom, they would never have known when they were fertile.

NFP to avoid pregnancy

The final, but greatest use of fertility education is to formulate it into a method of genuine “family planning”. The all-embracing term of “Natural Family Planning” emphasises that it is a non-invasive method based on education not intervention, that it has no health risks or side effects, and that it can be used to plan as well as to avoid pregnancy. In Africa it is called “Modern Scientific NFP” to distinguish it from the old Rhythm, Calendar Calculation Method. Perhaps the same title needs to be applied here to break through the barriers of prejudice that exist in the profession.

The Sympto-Thermal Method

The highest success rates in avoidance of pregnancy have been achieved by use of multiple indices as in the “Sympto-Thermal Method”. It combines the rules of the Billings Ovulation Method with the Temperature Method and teaches couples, the woman in particular:

  • how to observe the onset of the fertile mucus symptom so that intercourse can be avoided at the time of fertility.
  • how to keep a temperature chart to confirm the event of ovulation.

As the mucus disappears and the temperature rises, after three high readings, the rest of the cycle is absolutely infertile. The infertility of this latter phase, confirmed by Tietze, can be offered with relief to women with serious health risks, thus avoiding the need for sterilisation or the less effective continuous use of barrier methods.

As already explained, the mucus is observed visually and by sensation at the vulva. The mesh mucus with its “dry” feeling and the motorway mucus with its “wet” feeling have given rise to a simple teaching verse “When you’re dry, the sperm will die. When you’re wet, a baby you can get”. It is an over-simplification, but nonetheless a useful catch phrase for teaching. With experience, the use of a thermometer is reduced to cover only the days of fertile mucus plus the first three high readings.

Improved success rates in new studies

Through improved teaching programmes and good motivation of couples, the failure rates in modern studies are very low (Ryder 1995). Figures have been broken down to distinguish between method failures, teaching related pregnancies and user failure. Charting systems are varied and imaginative. My own system puts fertility back into the tapestry of nature. I equate the infertile time with autumn and winter and fertility with spring and summer. There is a colour scheme based on the seasonal changes of the trees, with a quick tick system as the symptoms appear. It is visual, easily read and has proved very popular.  Please go to for more info.

The National Association of NFP Teachers runs training programmes for teachers and users, and has a network of trained teachers around the country trying to provide a professional, but often voluntary service, for a need as yet unmet by the NHS. I have tried to demonstrate the level of misinformation in the community and regret that prejudice in the medical profession hinders development of NFP and thereby reduces patient choice. If I have succeeded in arousing interest and a desire for further information on fertility education and Natural Family Planning, please contact me at the address given.

C. Norman

Fertility Education Trust

218 Heathwood Road


CF14 4BS

For further information about please see Fertility Education and Education

Article first published in RCOG journal “The Diplomate”. It has been slightly modified for this info sheet to make it accessible to a wider audience.


  1. Billings E.L., Billings J.J., Brown J.B. & Burgen H. (1972) Symptoms and hormonal changes accompanying ovulation. Lancet 1:282-84
  2. Odeblad E. (1997) Cervical mucus and their functions. Journal of Irish College of Physicians and Surgeons 26:27-32
  3. Tietze C. (1970) Proceedings of the Eighth Annual Meeting of the American Association of Planned Parenthood Physicians, Boston, Massachusettes, USA. Advances in Planned Parenthood Volume VI
  4. World Health Organisation (1981) A prospective multi-centre trial of the ovulation method of natural family planning 2. Effectiveness phase. Fertility and sterility 36:591-598
  5. Ecochard R., Ecochard I, Dumeril B., Guibaud S., Leger A & Dumont M. (1984) Interet de l’ autoobservation de la glaire cervicale dans la determination de la periode fertile. Contacept. Fertil Sex 12:475-8
  6. Depares J., Ryder R.E.J., Walker S.M., Scanlon M.F. & Norman C.M. (1986) Ovarian ultrasonography highlights precision of symptoms of ovulation as markers of ovulation. British Med. Journal 292:1562
  7. Labbok M., Koniz-Booher P., Shelton J. & Krasovec K. (1992) Guidelines for breastfeeding in family planning and child survival programmes. Institute for International Studies in Natural Family Planning, Georgetown University, Washington DC
  8. Gray R.H., Campbell O.M. Apelo R et al. (1990) Risk of ovulation during lactation. Lancet 335:25-29
  9. Ryder R.E.J. (1995) Natural Family Planning in the 1990s. Lancet 346:233-




Written by Team Foresight

Team Foresight

Foresight is a pioneering charity which helps couples to conceive happy, healthy babies. By optimising health in both parents we support fertility and increase the chances of a successful pregnancy.