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Contraception
Corner
Just Say No Every Now and Then
Anita L. Nelson, MD; Miriam Zieman, MD
Today, we have remarkably convenient, reversible methods of
contraception that are as effective as sterilization. We have
hormonal methods of birth control that offer a wide range of
important health benefits, as well as provide contraceptive protection.
Despite these developments, there are many couples who, for personal,
cultural, and/or religious reasons, choose not to avail themselves
of these methods or of any of the barrier options. Instead, they
prefer to rely on techniques that are curiously referred to as “natural
family planning” (NFP) methods. More correctly, these techniques
are called “periodic abstinence” or the “fertility
awareness method” (FAM). In periodic abstinence, the couple
avoids intercourse during the at-risk days. In FAM, they use
another method (such as condoms or withdrawal) during the at-risk
days. To implement either form of “natural” family
planning, it is necessary to calculate when a woman is about
to ovulate or has recently ovulated and is vulnerable to pregnancy.
Is “natural family planning” truly “natural”?
Instead, it is more accurate to characterize these methods as “behavioral
methods” along with withdrawal and lactational amenorrhea.
As health care providers, we have a responsibility to those
couples who select these approaches to ensure that the methods
are as effective as possible in protecting against pregnancy.
While there are no medical contraindications to use of these
methods, they are not indicated for women with irregular menses,
such as women with polycystic ovarian syndrome, breast-feeding,
or perimenopausal hormonal fluctuations. Several techniques are
used to detect the at-risk days, but the typical failure rate
for periodic abstinence is 25%.1
The calendar or “rhythm” method is based upon analysis
of recordings of actual menstrual cycling. Because women frequently
do not record exact dates of their menses, this information must
generally be accumulated prospectively over 6 to 9 months, depending
on the consistency of the woman’s cycle length. From these
data, the extremes of cycle length are identified, and the days
of abstinence are calculated with the assumption that the sperm
survive 5 days, the ovum survives for 1 day, and the luteal phase
is 12 to 16 days long. Using these assumptions, the at-risk days
can be calculated using these simple rules:
- The first day of abstinence = the number of days of the
shortest cycle minus 18.
- The last day of abstinence = the number of days of the longest
cycle minus 11.
Using these formulas, it can be seen that the greater the variability
in a woman’s cycle length, the greater the number of days
of abstinence. A woman with a perfectly consistent cycle length
of 28 days would have to abstain during cycle days 10 to 17,
or 8 days per cycle. A woman whose cycle lengths varied between
26 and 30 days would have to abstain during cycle days 8 to 19,
or 12 days per cycle.
The Billings method or ovulation method relies on the changes
that ovarian hormone production has on cervical mucus. After
menses, the cervical mucus is scant and dry. It thickens and
increases in amount and stickiness until near ovulation, when
it becomes abundant, slippery, clear, and elastic under the influence
of estrogen. Under the influence of progesterone, the mucus becomes
thick, cloudy, and adherent. The woman typically assesses the
secretions at her introitus with her fingers or with a piece
of toilet paper before urinating each morning. Intercourse is
forbidden from the time the first day that secretions are detected
until the fourth day after the day of peak cervical secretions.
Because vaginal lubricant or ejaculate can mask subtle changes
in cervical mucus, sexual arousal and intercourse are restricted
to alternate days to permit accurate assessment of secretions.
Similarly, vaginal infections (eg, candidiasis, bacterial vaginosis)
and their topical therapies can confuse the assessment, so intercourse
should be delayed until these conditions have resolved. A variation
of the ovulation method is the TwoDay Method, which has the woman
refrain from intercourse if she has secretions either “today” or “yesterday.”2
Ovulation can be detected by measuring basal body temperature
(BBT) with a digital thermometer or expanded-scale mercury thermometer
at the same time each morning before arising. Just prior to ovulation,
many women note a temporary dip in baseline temperature followed
by a rise of at least 0.4°F, which is sustained until the
next withdrawal bleed. In some applications, intercourse is not
allowed until 3 days after the temperature rise. In others, intercourse
may be permitted until the initial temperature dip and resumed
3 days after the initial temperature rise. For women who do not
have initial temperature dips, they should consult prior months’ patterns
and abstain starting 1 week before she expects the temperature
rise. About 80% of women have interpretable BBTs. Other factors,
such as nocturnal arising and fever, may affect a woman’s
BBT.
The most comprehensive approach today is the symptothermal method,
in which women use some combination of the Billings technique,
the calendar method, and BBTs to determine at-risk days. In addition,
a woman can check the consistency of her cervix, which softens
and opens slightly with ovulation. If any of these indications
suggest impending ovulation, intercourse is delayed.
These methods help couples learn more about the reproductive
cycle, but they require several months of prospective data gathering
before they can be effectively implemented. Traditionally, women
learned their cycles and their physical signs of impending fertility
during long engagements prior to sexual debut. Today, women want
to start using these approaches more quickly, so new approaches
are needed. The Standard Days Method using CycleBeads has allowed
more rapid adoption of the calendar or rhythm method.3 It
is intended for women whose usual cycle length is 26 to 32 days
and can be used very easily in a low-literacy population. CycleBeads
is a string of colored beads with a black elastic band. The band
is moved over the red colored bead the first day of the cycle.
Each day after that, it is advanced over one of the dark beads.
Intercourse is allowed on these days. However, on the eighth
day of her cycle, she will advance to the first of 12 light beads
indicating the days of abstinence. The following beads are each
dark, representing safe days; bead 26 is darker than the others.
If a woman’s period starts before the darker bead, her
cycle was too short to rely on the beads. If she has not started
her menses by the last dark bead, her cycle is too long.
Although these warnings may be too late to protect her from
pregnancy during this cycle, if they happen more than once in
a year, she will know that this method is probably not appropriate
for her. Additional information about the Standard Days Method
and CycleBeads is available from the Georgetown University Institute
for Reproductive Health at http://www.irh.org/.
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| CycleBeads allows women a more rapid
adoption of the calendar or rhythm method. |
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In many European countries and Canada, handheld fertility detection
monitors for periodic abstinence have been available for years.
This method applies modern computer technology to identify safe
days. The most sophisticated of these is Persona, which has a
typical failure rate of about 12% and a method failure rate of
about 6%.4 A woman pushes a button when her menses
start each month. She opens the monitor daily to determine her
vulnerability to pregnancy. If it is a safe day, a green light
will illuminate; if it is a day of clear risk, a red light shines;
if the computer is not able to determine the risk, a yellow light
turns on. If the light is yellow, a woman puts a special strip
of test paper into a midstream urine sample and places it into
the analytic portion of the monitor. The machine scans the urine
for luteinizing hormone and estrone-3-glucuronide.
Within 1 minute, the results are displayed to the patient as
a red or green light. The data on the woman’s menstrual
cycle length and her urine test results are analyzed by the computer
to decrease the number of uncertain days requiring testing over
time. This unit was tested in the United States several years
ago, but it is not currently available in the United States.
It is probably prudent to advise patients of techniques that
do not work as well as existing methods. For example, it has
become popular to suggest ovulation detections kits to determine
at-risk days. Unfortunately, these kits are better suited to
identify the most fertile days and, in general, may
not provide adequate warning of impending ovulation to provide
safety during the end of the follicular phase. Additional concerns
are that there have not been studies reporting effectiveness
using these kits and they are expensive to use on an ongoing
basis.
REFERENCES
- Hatcher RA, Trussell J, Stewart F, et al. Contraceptive
Technology. 17th ed. New York, NY: Ardent Media Inc;
1998..
- Sinai I, Jennings V, Arevalo M. The TwoDay Algorithm: a
new algorithm to identify the fertile time of the menstrual
cycle. Contraception. 1999; 60(2):65-70.
- Arevalo M, Jennings V, Sinai I. Efficacy of a new method
of family planning: the Standard Days Method. Contraception.
2002;65(5):333-338.
- Guida M, Bramante S, Acunzo G, Pellicano M, Cirillo D, Nappi
C. Diagnosis of fertility with a personal hormonal evaluation
test [Italian]. Minerva Ginecol. 2003;55(2):167-173.
About ARHP
ARHP is a nonprofit,
national medical organization that has been educating front line
providers and their patients since 1963.
The organization and members are dedicated to educating physicians
and health care providers, and the public about important reproductive
health issues including contraception, sexually transmitted diseases,
menopause, abortion, sexuality, and infertility. ARHP contact
information: 2401 Pennsylvania Ave, N.W., Suite 350, Washington
DC 20037-1718; ph: (202) 466-3825; fax: (202) 466-3826; e-mail: arhp@arhp.org;
Web: www.arhp.org.
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