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Protection of Conscience Project

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Service, not Servitude
Background

"NO MORE CHRISTIAN DOCTORS"

Appendix "D"

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  Effectiveness
D2.1.1  Chart    (Click on chart to enlarge)

Birth Control Effectiveness, Chart

D2.1.2  Table    (Click on table to enlarge)
Birth Control Effectiveness Table
Sources:  

*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.


D2.2  Method of Measurement
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.

D2.3  Definitions
Perfect Use/Method Effectiveness
  • 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.
Actual/Typical Use/Use Effectiveness
  • 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.)

 

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