Pyper CM. Eur J Contracept Reprod Health Care. 1997 Jun;2(2):131-46.
Department of Public Health & Primary Care, Institute of Health Sciences, Oxford, UK.
Information about fertility awareness helps to fulfil the broader definition of the services many family planning clinics offer. Although information about natural family planning is requested by a small number of clients seeking family planning advice, many more clients benefit from information about fertility awareness. Fertility awareness is far more than just basic reproductive anatomy and physiology; fertility awareness involves understanding basic information about fertility and reproduction, being able to apply it to oneself, and being able to discuss it with a partner or with a health professional.
Fertility awareness is fundamental to understanding and making informed decisions about reproductive health and sexual health. If clients have a better understanding of fertility awareness, they are in a stronger position to make informed decisions about how they wish to manage their reproductive and sexual health, for example:
Serial ultrasound studies on the ovaries during the
menstrual cycle have confirmed the accuracy of the hormonal assays in
pinpointing the likely time of ovulation. Ultrasound studies have also
shown that subjective observations of the alterations in cervical mucus
and the basal body temperature rise are accurate indicators of the
Research on the chances of conception on each day of
the menstrual cycle, using hormonal assays to estimate the time of
ovulation, was carried out in 1994 by Weinberg and Wilcox. Their results
showed that the timing of sexual intercourse, in relation to ovulation,
strongly influences the chance of conception. Conception only occurred
during a 6-day interval that ended on the estimated day of ovulation.
The chances of conception fell to zero 24 hours after ovulation.
Several different methods of natural family planning are taught; some methods
depend on only using one of the indicators of fertility, others are
based on two or more indicators. The main indicators of fertility are:
observing the cervical mucus, recording the basal body temperature,
palpating the cervix and a calculation based on the cycle length.
Research studies performed using a combination of the indicators of
fertility show that the failure rate using a combination is less than
most of the studies which use a single indicator. In each case the
method failure is far lower than the user failure.