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Introduction
Trials of the Billings Ovulation Method carried
out in both developed and developing countries reveal high reliability,
effectiveness and satisfaction with the method.
The most recent large
scale trial was conducted in China.
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, Anhui, Kunmin and
Shanghai )/ Qian et al. |
1996-97 |
992 |
1 year |
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 |
2,059 |
21 months |
|
0.85% |
|
|
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
China
(Nanjing, Anhui, Kunmin and Shanghai )/
Qian et al. |
1,654 healthy women of proven fertility (having
at least one live birth), aged 24-35 years, with regular menstrual
cycles (3-7/24-35 days), to be cohabiting and enjoying their
husbands' support for participation in the trial, were enrolled.
The participants were mostly peasants and also workers and
white collars with different educational levels. They
were randomly divided according to the ratio 3: 2 into two
groups (the BOM group, 992 subjects, and the IUD group, 662
subjects) The observation was continued for 12 months. |
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, Anhui, Kunmin and Shanghai)/
Shao-Zhen QIAN, De-Wei ZHANG, Huai-Zhi ZUO, Ren-Kang LU, Lin
PENG, Chang-Hai HE and the Chinese Billings Ovulation Method Collaboration
Programme |
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. |
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