Trials of the Billings Ovulation Method

Introduction

Trials of the Billings Ovulation Method carried out in both developed and developing countries reveal high reliability, effectiveness and satisfaction with the method.

In China, the Nanjing Family Planning Instruction Institute and the Jiangsu Family Planning Research Institute in collaboration with Drs Evelyn and John Billings are conducting a significant controlled trial on the reliability of the method. The results of the first stage of this trial are in the process of publication.

It is extremely difficult to evaluate and compare fertility control methods in clinical trials because of the terms used and the variety of methods available. To understand the terminology a list of terms is included below.

TERMINOLOGY USED IN TRIALS

METHOD-RELATED PREGNANCY RATE

This indicates the number of pregnancies, expressed as a percentage, occurring when couples carry out correct instructions for a particular method. The correctly assessed pregnancy rate under these circumstances is an indication that the method has not covered a percentage of biological circumstances.

All fertility control methods have such failures, including the Pill, the IUD, and even sterilisation.

TEACHING-RELATED PREGNANCY RATE

This figure applies to pregnancies resulting from incorrect teaching of a method, or to misunderstanding by the user of the method.

CONTINUATION RATE

This is a guide to the acceptability of a method and is judged by the readiness of users to continue with a method over an extended period and to return to a particular method after a pregnancy.

TOTAL PREGNANCY RATE

This total figure includes pregnancies resulting from a failure of a particular method to cover all biological circumstances, misunderstanding of the method, risk-taking by couples, ambivalence towards pregnancy, and the decision by a couple to exercise the second option of achieving a pregnancy. Within the total pregnancy rate there may also be a number of pregnancies resulting from an act of intercourse when agreement fails between partners.

Consult the 1997 edition of The Billings Method, Controlling fertility without drugs or devices, by Dr Evelyn Billings & Ann Westmore for further reading on terminology and the trials reported in the following tables.

**SUMMARY of TRIALS**
Location/Investigator	Years	Couples	Cycles or years	Method related pregnancies		Teaching related pregnancies
China (Nanjing)/ Zuo et al.	1996-97	992	1 year (continuing)	0	0.0%	5 ^{(use- related)}	0.5%
Africa, Burkina Faso/Minister of Health and Social Action of Burkina Faso	reported in 1990	166	2,272	1	0.6%		1.7%
India, 5 States/Indian Council of Medical Research	1986-88	2,082	2 years		<1%
Indonesia/Family Health International USA	1986-88	>425		0*	0%
5 Nations-India, The Philippines, El Salvador, New Zealand, Ireland/World Health Organisation	1976-78	869	10,215		2.8%		3.9%
Australia (Victoria)/Ball	1976	122	1,626	4**	2.9%	8	5.9%
USA/Klaus	1975-77	1,090	12,282		1%
Australia (Melbourne)/Billings	1972	98	3-4 years	0	0%	0	0%
Tonga/Weissman	1970-72	282	2,503	1***	0.5%	2	1%

**Remarks**
* Indonesia/Family Health International USA	Multicentre study of three methods of NFP - 850 women entered the trial, more than half entered for the Billings Ovulation Method (BOM) - results for BOM only. At the end of this survey the study investigators recommended that the Billings Ovulation Method be included within the choices of family planning methods provided by the national programme in Indonesia.
Australia (Victoria**)/Ball	Indications were that sperm survival in one case was 5-6 days, 6-7 in two cases and 7-8 on one other. A sperm survival time of up to five days is credible in the presence of adequate amounts of fertile mucus, but present scientific knowledge does not allow a clear statement about sperm viability for longer than this.
***** Tonga**/Weissman	Some time later it was revealed by the couple who had reported a method-related pregnancy that they had in fact been aware of fertile signs at the time. Therefore in this trial the method-related pregnancy rate was zero.

**References**
Location/Investigator	Reference
China (Nanjing)/ ZUO Huai Zhi, BAI Li Qin, CHEN Hong, DONG Yu Feng, YANG Hui Ling, DOU Fang Bin, NI Xue Man, YANG Ming Ming, QIAN Shao Zhen, Evelyn L Billings, John J Billings	Evaluation of the Effectiveness of a Natural Fertility Regulation Programme in China
Africa, Burkina Faso/Minister of Health and Social Action of Burkina Faso	Minister of Health and Social Action of Burkina Faso, Bulletin d’Epidemiol. Et d’Inform. Socio.-Sanitaire, No. 17, 1990.
India, 5 States/Indian Council of Medical Research	Indian Council of Medical Research, "Optimism With Natural Family Planning for Fertility Regulation in India", Preliminary Report of a Five-State Study of the B.O.M. in India 1986 to 1988, presented at the Conference on "The Welfare of Women", St John’s College Hospital, Bangalore, India, January 1990.
Indonesia/Family Health International USA	S. Thapa, M.V. Wonga, P.G. Lampe, H. Pitojo, A. Soejoenoes, "Efficacy of Three Variations of Periodic Abstinence for Family Planning in Indonesia", Studies in Family Planning, 21:327-34, 1990.
5 Nations-India, The Philippines, El Salvador, New Zealand, Ireland/World Health Organisation	World Health Organisation, Task Force on Methods for the Determination of the Fertile Period, Special Programme of Research, Development and Research Training in Human Reproduction, "A Prospective Multicentre Trial of the Ovulation Method of Natural Family Planning, I, The Teaching Phase", Fertility and Sterility, 36.152, 1981. WHO, op. cit. Phase II. WHO, op. cit., Phase III. WHO, op cit., Phase IV.
Australia (Victoria)/Ball	M. Ball, "A prospective field trial of the Ovulation Method", European Journal of Obstetrical and Gynaecological Reproductive Biology, 6/2, 63-6, 1976.
USA/Klaus	H. Klaus et al., "Use effectiveness and client satisfaction in six centres teaching the Billings Ovulation Method", Contraception, 19:6, 613, 1979.
Australia (Melbourne)/Billings	E.L. Billings, Report to Workshop on the Ovulation Method, Sydney, 1973.
Tonga/Weissman	M.C. Weissman, J. Folaiki, E.L. Billings, J.J. Billings, "A trial of the Ovulation Method of family planning in Tonga", Lancet, 813-16, 14 October, 1972.