"NO MORE CHRISTIAN DOCTORS"
Appendix "D": Statistics
D2. Effectiveness of Birth Control Methods
Introduction
What is provided here is not exhaustive. It is intended only to
provide the reader with sufficient information to understand the factors
and issues likely to be involved when health care workers decline to
provide contraception services for reasons of conscience.
Contents
1. Effectiveness of Birth
Control Methods
2. Method of
Measurement
3. Definitions
D2.1.1 Chart (Click on chart to enlarge)
D2.1.2 Table (Click on table to enlarge)
*Trussell J. Contraceptive Efficacy. In Hatcher RA, Trussell J, Nelson
AL, Cates W, Kowal D, Policar M. Contraceptive Technology: Twentieth
Revised Edition. New York, NY: Ardent Media, 2011. Cited in
Contraceptive Technology, Table 3-2:
Percentage of women experiencing an unintended pregnancy during the first
year of typical use and the first year of perfect use of contraception, and
the percentage continuing use at the end of the first year. United
States. (Accessed 2014-02-13)
(1) Ball M, "A prospective field trial of the Ovulation Method."
European Journal of Obstetrical and Gynaecological Reproductive Biology,
6/2, 63-6, 1976. Cited in Billings, Evelyn and Ann Westmore, The
Billings Method: Controlling fertility without drugs or devices.
Toronto: Life Cycle Books, 1998, p. 220
(2) Kyo Sang Cho, "Report to World Health Organisation Conference,"
Geneva, February, 1976. Cited in Billings, Evelyn and Ann Westmore, The
Billings Method: Controlling fertility without drugs or devices.
Toronto: Life Cycle Books, 1998, p. 221
(3) Wade, MF et al, "A randomised prospective study of the use
effectiveness of two methods of natural family planning: an interim report."
American Journal of Obstetrics and Gynecology, 134, 628, 1979. Cited in
Billings, Evelyn and Ann Westmore, The Billings Method: Controlling
fertility without drugs or devices. Toronto: Life Cycle Books, 1998, p.
223
(4) Minister of Health and Social Action of Burkina Faso, Bulletin
d’Epidemiol. et d’Inform. Socio-Sanitaire, No. 17, 1990. Cited in Billings,
Evelyn and Ann Westmore, The Billings Method: Controlling fertility
without drugs or devices. Toronto: Life Cycle Books, 1998, p. 225-226
(5) Bhargava H, Bhatia JC, Ramachandran L, Rohatgi P, Sinha A, "Field
trial of billings ovulation method of natural family planning."
Contraception. 1996 Feb;53(2):69-74.
(6) Frank-Herrmann P, Heil J, Gnoth C, Toledo E, Baur S. Pyper C,
Jenetzky E, Strowitzki T, and Freund G. "The
effectiveness of a fertility awareness based method to avoid pregnancy in
relation to a couple's sexual behaviour during the fertile time: a
prospective longitudinal study." Hum. Reprod. (2007) 22 (5): 1310-1319.
doi: 10.1093/humrep/dem003 (Accessed 2014-02-13)
(7) Hilgers TW, Stanford JB. "Creighton Model NaProEducation Technology
for avoiding pregnancy. Use effectiveness." J Reprod Med. 1998
Jun;43(6):495-502.
(8) Freundl G, Frank-Herrmann P, Godehardt E, Klemm R, Bachhofer M.
"Retrospective clinical trial of contraceptive effectiveness of the
electronic fertility indicator Ladycomp/Babycomp." Adv Contracept. 1998
Jun;14(2):97-108.
Pearl Index
The number of pregnancies resulting from the use of a birth control
method per 100 woman years of exposure.
If 100 women use a product / method for one year -
- 15 pregnancies after one year = 85% effectiveness (15% pregnancy
rate)
- 10 pregnancies after one year = 90% effectiveness (10% pregnancy
rate)
- 5 pregnancies after one year = 95% effectiveness (5% pregnancy rate)
Note -
While the pregnancy rate remains the same, the number of pregnancies
continue to increase over time. That is -
- 5 pregnancies after one year = 95% effectiveness (5% pregnancy rate)
- = 10 pregnancies after two years
- = 15 pregnancies after three years
- = 20 pregnancies after four years, etc.
- Refers to the effectiveness of a method or product when it is used
consistently and exactly as directed. In the case of manufactured
products (such as condoms), this includes the correct storage of the
product.
- Refers to the effectiveness of a method or product as it is
typically or actually used.
- Variations in effectiveness result from a number of factors,
including
- product quality
- drug interactions
- failure to use consistently as directed
- population group differences (age, marital status,etc.)