Natural Family Planning in the 1990s

The Lancet, Bob Ryder, Hubert Campbell

To the lay person, natural family planning (NFP) equates with the "rhythm method" or "Roman roulette" and therefore tends to be considered as mostly a matter of chance, resulting in unplanned pregnancies and large families.

The medical and scientific communities generally take a similar view and the tone of comments in this journal has been dismissive.

For example, Dr Joyce Poole, writing in The Lancet, declares that "natural family planning . . . has been shown in many reputable trials to be ineffective in countries where education is rudimentary and feminine hygiene is poor". (ref.RR1)

She does not give references for these trials, but others who have argued similarly refer to the World Health Organisation multi-centre trial of the Ovulation method of NFP which was undertaken in 1975 -79 (ref.RR2-6) One of us (HC) was the medical statistician for that study, whose primary object was to determine what proportion of women of many different cultures could be taught to recognise changes in the cervical mucus, around the time of ovulation, that had been described in 1972 in Australian women. (ref.RR7). A second object, if these could be recognised, was to determine whether women would use these changes as a method of restricting fertility; and a third was to identify social, medical, and subjective factors influencing these observations.

In other words, the WHO study was not primarily a trial of fertility control.

The main conclusions were that:

We now know that the cervical mucus, which at ovulation becomes reminiscent of raw egg-white, identifies ovulation with precision (ref. RR8) and is essential for fertility. (ref.RR9,10).

It has several components with different functions:

  •     G     mucus occurs during the infertile phase and forms a barrier in the lower cervix impenetrable by sperm;

  •     L     mucus appears as the oestrogen level rises and blocks the passage of low-quality sperm;

  •     S     mucus conducts high quality sperm through the L mucus to storage crypts at the upper end of the cervix where they are sealed in by a mucus plug; and

  •     P     mucus appears just before ovulation and in conjunction with Z secretion disolves that mucus plug, releasing sperm from the cervical crypts and facilitating their further passage towards conception. (refs RR9,10).

The knowledge gained through the WHO trial and subsequent experience has given NFP organisations and teachers a much greater understanding of the fertile and infertile phases, so that total pregnancy rates have been steadily falling.

The following are the total pregnancy rotes of NFP studies so far reported in the 1990s (they include studies conducted in Moslem, Hindu, Chinese, and Christian cultures): -

Country Pregnancies/
lOO woman yr
United Kingdom 2.7 11
Indonesia 2.5 12
Indonesia 10.3 12
India 2.0 13
Germany 2.3 14
Liberia 4.3 15
Zambia 8.9 15
Europe 2.4 16
Europe 10.6 16
China 4.4 17
Belgium 1.7 18

The three studies with results greater than 5 were all trials of atypical NFP approaches or teaching methods.

The results con be compared with reported pregnancy rates of between 0.18 and 3.6 for artificial contraceptive methods in well-motivated couples.(ref RRl9)

Pregnancy rates for artificial contraceptive methods may be considerably higher than this in less well motivated couples and, indeed, may be greater than 20.(refs. RR2021)

It is not helpful to hark back to the pregnancy rates of studies conducted before NFP came of age.

The cheapness of NFP makes the readiness of Poole and others (ref.RR22) to dismiss it as an option in the developing world seem ill-advised.

It is the only method that empowers a couple to control their fertility irrespective of economic status and independently of distributors of pills and condoms.

NFP allows couples to avoid or achieve pregnancy.

Those wishing to achieve pregnancy will have extremely high pregnancy rates; those strongly motivated to avoid pregnancy will have extremely low pregnancy rates (approaching zero in a huge study amongst the poor and illiterate in the slums of Calcutta (refs. RR23-25)

One criticism of NFP is that the necessary periods of abstinence may be detrimental to the marital relationship and the family, (ref.RR26) and even that such abstinence is unnatural.

For similar reasons many expected that the widespread availability of the oral contraceptive pill would benefit marriages, families, couples, and their children.

In fact the increasing use of the pill has been contemporaneous with a massive increase in marital and family breakdown.

This temporal association does not prove a link, but Billings (ref.RR27) comments that the demand associated with artificial contraception for "uninterrupted availability of sexual intercourse . . . is an unrealistic expectation in any marriage and sets the course for the breakdown of the marriage" .

Critics of NFP complain that the problem is that men must, but cannot, co-operate (refs. RR 28, 29).

Proponents object to this denigration of men (ref.RR30) and suggest that the requirement for men and women to co-operate is a strength of NFP (ref.RR31)

As Jarvis puts it: "Understanding and co-operation are necessary for NFP to work, but also for relationships to work.

Couples in which women are forced to submit to men for sex require counselling, not pills . . . sexual intercourse is supposed to be an intimate expression of love, a choice freely made, and not a means of using others to satisfy an ‘irresistible physiological urge‘. (ref.RR30).

In some developing world countries, in particular, it is suggested that women are obliged to submit to their husbands‘ demands; (ref.RR29) however, in these circumstances the mutual discipline of NFP can foster marital harmony and enhance the relationship. (refs.RR31,32).

Women in particular report that the times of avoidance of sexual intercourse can lead to the expression of non-genital physical love which is longed for and helps their sexual responsiveness. (ref.RR31).

Whilst some object that the fertile phase is the time of strongest sexual desire, (ref.RR29) others suggest that the monthly "honeymoon" at the time of resumption after the fertile phase provides benefits within the sexual relationship. It is being suggested that the "sexual revolution" of the last 20-30 years has caused marital and family breakdown on a massive scale and at vast cost.(ref.RR33).

One wonders whether NFP might not be the antidote.

Whatever one‘s views on the relative merits of artificial contraception versus NFP, those with an interest in the rights of women should be concerned that women world-wide are not being informed of the symptoms of ovulation which are so easily and universally recognisable. (refs.RR2,24).

Since women are potentially fertile for no more than six to eight days in the cycle, (ref.RR24) these easily recognised symptoms empower women through the knowledge they impart regarding their state of fertility.

Many women are dissatisfied with artificial contraceptive methods and yet do not know of the NFP alternative.

Similarly, many sub-fertile women who are desperately trying to achieve conception are not being given this basic information that would maximise their chances.

Whether one looks at it from the ecological, feminist, economic, family, or just plain common-sense point of view, all women are entitled to this simple and fundamental information.

Lancet Vol. 346 July 22, 1995 pp233-234

Department of Endocrinology,
City Hospital NHS Trust,
Dudley Road, Birmingham
B18 7QH, UK

(REJ Ryder MRCP)


Pwll Coch Uchaf,
St Mellons,

(Prof H Campbell FRCP)

Correspondence to: Dr Bob Ryder


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  • 32 Howitt-Wilson MB Cheap effective and free of side effects BMJ 1993; 307: 1357-58

  • 33 Dixon P The rising price of love London: Hodder & Stoughton, 1995

Lancet - Vol 346 July 22, 1995

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