HOW NFP WORKS

[Billings Ovulation Method of NFP][Symptothermal Method of NFP][The Medical Point of View]

The Medical Point of View

The most important event in a fertile cycle is ovulation, the release of a ripe egg (ovum) from the ovary. The time from the beginning of menstruation until ovulation is called the pre-ovulatory phase.  The time from ovulation until the beginning of the next menstruation is called the post ovulatory phase.  When the mechanism of ovulation functions normally the interval between ovulation and the next menstruation is 11 to 16 days, whatever the length of the cycle.  This is called the luteal phase.

This ovarian activity is controlled by an area of the brain called the hypothalamus which itself governs the activity of the pituitary gland.  The pituitary gland produces two hormones directly concerned with fertility, the Follicle-Stimulating Hormone (FSH) and Luteinising Hormone (LH).

The pituitary hormone affects the ovaries. FSH causes follicles to commence maturing in the ovaries.  As the follicles mature the ovary produces the ovarian hormone, Oestrogen, which has an effect on the cervix causing it to produce special mucus which is vital for sperm survival, and on the endometrium ( the lining of the uterus) causing it to develop ready for pregnancy, should conception occur.

The luteinising hormone, LH, is released from the pituitary gland in increasing amounts when the ovum is nearing maturity.  The LH triggers ovulation and the production of another ovarian hormone, Progesterone, which changes the sensation that the woman experiences at the vulva, due to the cervical mucus which alerts her to the fact that ovulation is imminent.  The increased Progesterone causes a rise in the basal body temperature and together with Oestrogen acts to maintain and support the endometrium in readiness for implantation.

If conception does not take place, the level of ovarian hormones ( Oestrogen and Progesterone) begins to fall from the sixth day of the luteal phase, with drawing the support for the endometrium resulting inevitably in menstruation.  If conception does occur, the fertilized ovum (embryo) travels along the fallopian tube and implants in the uterus from the sixth to the twelfth day following conception.

Knowledge of these facts and recognition of where a woman is in her cycle according to her individual symptoms of infertility, potential fertility and the time of ovulation, enables a couple to plan to achieve or avoid a pregnancy as they choose.  The woman is taught to keep a chart of her cycle which gives very accurate information about her fertility and reproductive health.  Doctors are increasingly recognising the value of the information contained in a woman's chart in understanding her gynaecological health and the possible source of pathology.

The Ovarian Hormone Monitor, developed by Professor James B Brown, Emeritus Professor of Gynaecology, University of Melbourne, is used in some cases to accurately track a woman's ovarian hormonal profile throughout her cycle if a problem is suspected from her charting.

The veracity of this information has been proven by exhaustive scientific research. Modern methods of natural family planning have comparable success rates to the combined oral contraceptive pill and significantly better that the mini pill and barrier methods ( condom, IUD, Diaphragm).