Contraception, Health, - Fertility awareness

Fertility awareness methods identify the relatively few
“fertile days” of each menstrual cycle: the couple then
avoids genital sexual contact during those days. The
number of fertile days can range from 7 to 15 days
each cycle. Many couples prefer these methods
because no hormones, chemicals or appliances interfere
with their sexual activity. There are several
methods typically classified as “fertility awareness.”
Their efficacy varies.
“Calendar” rhythm, a method that predicts the
fertile days by “extrapolating” from the length of the
previous menstrual cycles, is historically unreliable.
The symptothermal methods of natural family
planning incorporate predictable physiological changes
that coincide with ovulation or the immediate
period prior to ovulation. “Thermal” refers to
the characteristic temperature elevation associated
with progesterone levels.
Just prior to ovulation, a woman’s temperature
declines approximately 0.1 to 0.2 C from her usual
baseline and then rises 0.5 to 0.6 C and remains
elevated for 12 to 15 days until the onset of menstruation.
These changes are best assessed by a woman
taking her “basal body temperature,” or the temperature
each morning at the same time daily before
rising, eating, drinking, or smoking.
Unfortunately other conditions may affect temperature,
including febrile illness and alcohol
consumption. Women can also use non-prescription
kits that measure the presence in urine of leutenizing
hormone. However, these kits are expensive to use
in this manner. “Sympto” includes the predictable
physiological changes associated with ovulation
such as Mittelschmerz pain (mid cycle ovulatory
pain), moliminal symptoms (breast tenderness) and
changes in cervical consistency. For many couples,
the most consistent “symptom” is the predictable
change in cervical mucus that correlates with various
portions of the menstrual cycle. Classes taught by
experienced health educators or couple-to-couple
instruction help couples to reliably recognize and
interpret mucus changes and establish the days
that require “abstinence.” The couple who wishes
to identify the time of peak fertility can also use
these methods.
Lactational amenorrhea is another fertility awareness
method described in greater detail under the
section “Special populations.” Its efficacy was assessed
in a recent Cochrane Review.24
The Cochrane collaborative identified three trials,
one from Colombia and two from California. Because
of significant methdologic weaknesses including
issues in recruitment, high drop-out rates, and poor
research methods they were unable to compare how
well fertility awareness-based methods work.

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