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

Frank-Herrmann P; Heil J; Gnoth C; Toledo E; Baur S; Pyper C; Jenetzky E; Strowitzki T; Freundl G

doi:10.1093/humrep/dem003

Fertility Awareness · Effectiveness

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

Frank-Herrmann P, Heil J, Gnoth C, Toledo E, Baur S, Pyper C, Jenetzky E, Strowitzki T, Freundl G

Published May 2007 Human Reproduction (Oxford, England), 22(5), 1310-1319

DOI 10.1093/humrep/dem003 PMID 17314078

RRM Academy Synopsis

1.8 per 100 women had unintended pregnancy in 13 symptothermal cycles

Women using the symptothermal method had 1.8 unintended pregnancies per 100 women over 13 cycles in a German prospective cohort of 900 women. With abstinence during the fertile time, the rate was 0.43 per 100 women and 13 cycles.

Key Findings

The 900 women supplied 17,638 cycles meeting the inclusion criteria. The unintended pregnancy rate was 1.79 per 100 women after 13 cycles, similar in the first 3 months and in later months.
Per 100 women and 13 cycles, the rate was 0.43 with abstinence in the fertile time (95% CI 0.05 to 1.55). It was 0.59 with protected intercourse (95% CI 0.07 to 2.13).
Cycles with unprotected intercourse in the fertile time showed a significantly higher rate, up to 7.5% per year. In 16 of the 22 pregnancy cycles, unprotected intercourse occurred in the fertile time.
Among 322 women using only the symptothermal method and 509 who occasionally added barriers, rates at 13 cycles were 1.62 and 2.02 per 100 women, without a statistically significant difference.
Dropout for dissatisfaction or difficulties with the method, including a switch to another method, was 9.2 per 100 women at 13 cycles. Loss to follow-up was 6.7% after 13 cycles.

Interpretation

The study is a prospective observational cohort. Women began with their first symptothermal method cycle and were asked to record all sexual behavior. Pregnancy rates were then calculated against the cycles in which each behavior occurred, using the perfect/imperfect-use model. Participants were women aged 19 to 45 with no known history of infertility who intended to avoid pregnancy and were taught the method by accredited teachers. The authors note that the motivation of couples and teachers may partly explain the high use-effectiveness rates.

RRM Context

Charting builds body literacy, and Restorative Reproductive Medicine (RRM) relies on it. The symptothermal method links daily temperature and mucus signs to the cycle, and clinicians use the same signs to assess a couple.

Our editorial summary of this paper, not the article's abstract.

Abstract

Background

The efficacy of fertility awareness based (FAB) methods of family planning is critically reviewed. The objective was to investigate the efficacy and the acceptability of the symptothermal method (STM), an FAB method that uses two indicators of fertility, temperature and cervical secretions observation. This paper will recommend a more suitable approach to measure the efficacy.

Methods

Since 1985, an ongoing prospective observational longitudinal cohort study has been conducted in Germany. Women are asked to submit their menstrual cycle charts that record daily basal body temperature, cervical secretion observations and sexual behaviour. A cohort of 900 women contributed 17,638 cycles that met the inclusion criteria for the effectiveness study. The overall rates of unintended pregnancies and dropout rates have been estimated with survival curves according to the Kaplan-Meier method. In order to estimate the true method effectiveness, the pregnancy rates have been calculated in relation to sexual behaviour using the 'perfect/imperfect-use' model of Trussell and Grummer-Strawn.

Results

After 13 cycles, 1.8 per 100 women of the cohort experienced an unintended pregnancy; 9.2 per 100 women dropped out because of dissatisfaction with the method; the pregnancy rate was 0.6 per 100 women and per 13 cycles when there was no unprotected intercourse in the fertile time.

Conclusions

The STM is a highly effective family planning method, provided the appropriate guidelines are consistently adhered to.

Topics

Fertility Awareness Effectiveness Typical and Perfect Use

Fertility Awareness › Effectiveness › Typical and Perfect Use

Thomas Strowitzki, Petra Frank-Herrmann, Günter Freundl

Tom Strowitzki, T Strowitzki, P Frank-Herrmann, G Freundl

PMID 17314078 17314078 DOI 10.1093/humrep/dem003 10.1093/humrep/dem003 Frank-Herrmann et al. 2007, Frank-Herrmann 2007

Keywords

Adult, Body Temperature, Cervix Mucus/physiology, Family Planning Services/education, Female, Fertility, Health Knowledge, Attitudes, Practice, Humans, Longitudinal Studies, Male, Middle Aged, Natural Family Planning Methods, Ovulation Detection/methods, Patient Satisfaction, Pregnancy, Unplanned, Prospective Studies, Sexual Behavior

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

1.8 per 100 women had unintended pregnancy in 13 symptothermal cycles

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

Related research

Keywords