Comparison of Natural Family Planning (NFP) effectiveness with other methods of fertility regulation

STUDIES on the Effectiveness of NFP using the Pearl Index

Comment on Table 4-1: Table 4-1 outlines the effectiveness of the ‘symptothermal method’ (STM) of natural family planning in avoiding pregnancy, as documented in recent European studies using the Pearl Index.

Pearl indices in studies of Symptothermal (STM) Method

Location of the study

Year

Pearl Index (PI)

Ref

Germany (Double-Check Method)

2007

(0.4)* , 1.8

1

Germany (STM); (Double-Check Method not specified)

1991

2.3

2

Europe (Double-Check Method)

1989- 92

2.5

3

Table 4-1; Effectiveness studies (Pearl Index): Results showing the effectiveness of the symptothermal method of natural family planning in pregnancy avoidance as measured by the Pearl Index. (Adapted from the article on the internet by David Aldred4; *the figure in brackets is for ‘perfect use’, i.e. the use of the method strictly adhering to its rules. The remaining figures are ‘actual use’ figures, i.e. the ‘use effectiveness’, which is the sum of all the unintended pregnancies whether due to method or user failure).

References:

  1. Frank-Hermann P. et al; ‘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; Human Reproduction; Feb 2007; p1-10.
  2. Frank-Herrmann et al; ‘Effectiveness and acceptability of the symptothermal method of natural family planning in Germany; Am J Obstet Gynecol 1991; 165; 2052-4.
  3. Freundl G.; Prospective European multi-center study of natural family planning (1989-1992): interim results; Advances in contraception; 1993, 9; 269-283.
  4. Aldred, David; http://nfpsite.aldred.org/effect.html

 

STUDIES on NFP Effectiveness in comparison with other methods of fertility regulation using the Pearl Index

Comment on Table 4-2: Table 4-2 demonstrates that natural family planning is as effective as the contraceptive pill and IUD in pregnancy avoidance.

Pearl Index for various family planning methods*

Method

Pearl Index – ‘Perfect use’

Pearl Index ‘Actual Use’

Contraceptive Pill

(Pearl Index figure from ref 4 below)

0.1-0.5

3

** Natural Family Planning (NFP),

STM Double-Check

(Pearl Index figure  from ref 3 below)

2.5

Intra Uterine Device (IUD)

(Pearl Index figure from ref 4 below)

1.5

2

Male Condom

(Pearl Index figure from ref 4 below)

3

12

Table 4-2; Comparison of the effectiveness of NFP with other family planning methods: The ‘actual use’ figures for the various family planning methods quoted in Table 4-2 show that there is no significant difference in the rate of unintended pregnancies in those women who use natural family planning, with those who use artificial methods e.g. the ‘Pill’ or the IUD to regulate fertility. The ‘actual use’ rate for male condom users is significantly higher than for other methods.

*These figures (other than those for natural family planning) are from the article by David Aldred4 on the internet ; (for the figure for natural family planning see Table 4-1, and the text ** below). In his article, Aldred4 quotes figures from a standard reference text on the subject, i.e. “Contraceptive Technology by Hatcher, Trussell, Stewart et al; 16th edition; Irvington publishers, New York, 1994″. The figures for natural family planning in Table 4-2 are not quoted from ‘Contraceptive Technology’ as the authors lump all possible methods of natural family planning together under the term ‘periodic abstinence’ including those which were outdated by the mid 1940s,4 instead the NFP figures are from Freundl.3 (see next paragraph)

**The natural family planning figure quoted in Table 4-2 refers to reference 3 below, i.e. Freundl et al 1989-1992 European study, pages 278, 280 and Table 10 on page 279, as it uses the Pearl index measurement. This figure is the total use-effectiveness of the symptothermal double-check method in 7404 cycles. Use-effectiveness is calculated on the sum of all the unintended pregnancies (UIP) whether due to user or teaching failure, see page 277.

References:

  1. Frank-Hermann P.et al; ‘The effectiveness of a fertility awareness based method to avoid pregnancy inrelation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study; Human Reproduction; Feb 2007; p1-10.
  2. Frank-Herrmann et al; ‘Effectiveness and acceptability of the symptothermal method of natural family planning in Germany; Am J Obstet Gynecol 1991; 165; 2052-4
  3. Freundl G.; Prospective European multi-center study of natural family planning (1989-1992): interim results; Advances in contraception; 1993, 9; 269-283.
  4. Aldred, David; http://nfpsite.aldred.org/effect.html

 

To be most effective, the woman must be taught the Symptothermal Double-Check Method by a qualified natural family planning teacher.

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