Fertility Awareness and Natural Family Planning

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:

1. Fertility awareness information is used to help couples to plan
   pregnancies as well as to avoid them. This can be helpful to couples who
   are having difficulty conceiving, for the timing of intercourse or for
   the timing of some of the sub-fertility investigations.
2. The information is also useful when helping couples to understand how
   each method of family planning works--how the family planning method
   interrupts normal fertility, how the method will fail if not used
   correctly, and how fertility returns when the method is discontinued.
3. Women who are fully breastfeeding value the knowledge about reduced
   fertility, as do women during the perimenopausal years who value being
   given clear information about their declining fertility.
4. When counselling couples about the importance of avoiding sexually
   transmitted diseases it is important they understand sexually
   transmitted diseases may damage their fertility.
5. Couples who choose only to use a barrier method during the time they
   think the woman is fertile are a group who do not readily identify
   themselves to family planning providers. These couples often do not have
   adequate information about fertility awareness. Advances in technology
   and the understanding of ovulation, ovum and sperm survival have
   confirmed that the guidelines used to teach fertility awareness and
   natural family planning effectively identify the fertile phase of the
   menstrual cycle.

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
fertile phase.

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.