'Natural family planning' (NFP) is a method of birth control based on a woman's knowledge of the phases of her ovulation cycle, which recurs more or less monthly. During each cycle a woman goes through a 'fertile period' and an 'infertile period'. As a means of contraception (or 'pregnancy avoidance') a couple will refrain from having sexual intercourse during the fertile period. Also known as 'periodic abstinence', natural family planning is a method chosen by many couples who do not wish to use more interventionist methods for personal, medical or religious reasons. Other than total abstinence, it is the only form of birth control approved by the Catholic Church.
Conversely, a woman who wishes to become pregnant is able to aid conception by ensuring she has intercourse during the fertile period. Knowledge of when her fertile period is occurring is also necessary if a woman is undergoing assisted reproduction (ART) at a fertility clinic.
The first periodic abstinence method of birth control with any scientific basis came to be known as 'the rhythm method' because it was explained in 1932 in a book, 'The rhythm of sterility and fertility in women' by Dr Leo J. Latz. Initially the 'rhythm method' was based on predicting the day of ovulation by counting days backwards from the expected first day of menstruation.
Since the 1930s there has been increased understanding of the naturally occurring signs and symptoms of the fertile and infertile phases of the ovarian cycle, allowing more reliable technologies to be developed that help women recognise and chart physiological changes. For example, some methods are based on monitoring changes in body temperature or cervical mucus. More recently devices have been developed that detect cycles of hormone levels in a woman's body through testing of urine.
In the 1980s Professor James B. Brown and his collaborators at the Royal Women's Hospital in Melbourne devised an ovarian monitor for home use that could detect both the oestrogen rise that marks the beginning of fertility and the rise of progesterone at the end of fertility, by biochemically testing samples of a woman's urine. This was the first procedure of its kind that could be done with laboratory accuracy using relatively inexpensive equipment at home. Professor Brown's ovulation monitor, or 'Ovulation Meter', first became available to the public in 1986. The monitor underwent successive improvements and by 2003 the procedure remained internationally recognised as the only home test that could detect changes in the levels of both hormones on a daily basis.
The procedure for testing the urine is not simple and it is time-consuming, but is superior to other home tests because of its accuracy. Couples are trained in its use and are advised to take advantage of the phone, fax or email advisory service offered by St Michael NFP Services Pty Ltd, the company that manufactures and distributes the ovarian monitor.
The Model OM5 example of Brown ovarian monitor in the Powerhouse collection was donated by the Australian Council of Natural Family Planning in Sydney, an organisation associated with the Catholic Church in Australia.
Curator of health and medicine
Borek, A., Methods of family planning based on autoobservation and self-evaluation of the ovarian cycle.
Brown, J.B., 'Monitor update June 2002', St Michael NFP Services Pty Ltd information sheet (unpubl.)
Brown, J.B., 'Monitor update April 2003', St Michael NFP Services Pty Ltd information sheet (unpubl.)
Brown, J.B., Holmes J., & Barker G, 'Use of the Home Ovarian Monitor in pregnancy avoidance', Am J Obstet Gynecol., 165(6 Pt 2), December 1991:2008-2011 (Abstract available at PubMed - National Library of Medicine/ National Institutes of Health, USA
Cavero, C, 'Using an ovarian monitor as an adjunct to natural family planning', J Nurse Midwifery, 40 (3), May-June 1995, 269-276 (Abstract at PubMed - National Library of Medicine/ National Institutes of Health, USA
Siedlecky, Stefania, and Wyndham, Diana, Populate and perish: Australian women's fight for birth control, Sydney: Allen & Unwin, 1990.
Smyth, Kevin, St Michael NFP Services Pty Ltd, pers.comm. 16 February 2006.
(All websites sighted 16/02/2006)