Self-Monitoring of Fertility Hormones: A New Era for Natural Family Planning?

Natural family planning (NFP) methods have served many generations well, and in particular, the symptothermal or symptohormonal methods. The comparison of daily mucus and temperature records for individual cycles with daily hormone measurements, which is now possible, shows that some of the assumptions underlying NFP may not be completely accurate. The various methods are inadvertently depending on an element of chance, which, of course, cannot be known by the NFP user. However, it is statistically inevitable that such errors will result eventually in an unexpected pregnancy, and these discrepancies are the likely reason for the method failures. Further research and integration of home hormone measurements with NFP symptoms are needed.

Traditional NFP methods, based on the observations of temperature, mucus, and luteinizing hormone, can work well. However, these data are sometimes difficult to interpret, and significant changes in the variables are sometimes "missing" from some cycles. Changes in these variables are elicited by the estrogen and progesterone released from the ovaries. It follows that the direct measures of events in the ovaries are the levels of estrogen and progesterone or their derivatives in blood or urine. Measurements of urinary derivatives of estrogen and progesterone can be used to monitor the ovaries directly and are clearer indicators than traditional NFP methods.