Introduction
Fertility is a transient biological state that depends on the fertility
potential of the couple. During a women’s lifetime, the ovary
will go through different states of hormonal secretion and ovulation.
The concept of the ovarian cycle as a continuum considers that all
types of ovarian activity encountered during the reproductive life
are normal responses to different environmental conditions in order
to ensure the health of the mother and child.
During the first two years after menarche, occasional anovulatory
cycles may occur. However, subsequently, a healthy ovary will exhibit
regular monthly ovulations, characterized by a 25 to 36 day cycle
(32, 33, and 35). The ovulatory cycles are normally only interrupted
by pregnancies and breastfeeding. Normal ovulatory activity and
fertility are restored following pregnancy and breast feeding, however,
stress or excessive exercise may result in a chronic ovulatory dysfunction
that requires therapy. Anovulatory cycles frequently occur as menopause
approaches. This is an expected part of woman’s reproductive
life cycle.
The use of the ovarian monitor has made it
possible to identify hormonal variations during different
periods of a woman’s life and to correlate these changes
with the mucus patterns (5, 6, 7). Thousands of measurements
have been recorded for this purpose around the world, including
Chile. These investigations have raised an enormous amount
of information (24, 24). The amount and type of mucus secreted
by the cervix changes through the ovarian cycle in response
to fluctuating hormonal levels (26, 30 and 31). Mucins are
the main components of mucus (18). To date a total of 13 distinct
mucin genes have been identified (11,18). Mucins are categorized
into 3 groups on the basis of their structural properties:
membrane spanning (MUCs 1, 3, 4, 12 and 13, gel forming (MUCs
2, 5AC, 5B and 6) and small soluble (MUC 7). The four large
gel-forming mucin genes are located on chromosome 11.p15.5
(12,18). Mucin 5B is the major gel forming mucin expressed
by the endocervical epithelium and its expression peaks at
midcycle (10). Message levels for mucin 4 also peak at midcycle.
Two main types of cervical mucus have been described: oestrogenic
and progestative. According to O’deblad’s model,
the oestrogenic type can be subdivided in L, S and P subtypes
(4). The L subtype is the most abundant type of mucus during
the periovulatory period and the P subtype appears close to
ovulation (8). Message for all mucins diminishes as progesterone
levels increase in blood. (11) During the luteal phase the
progestative type of mucus is present. |
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Estrogenic types of mucus: EP, ES, EL |
G mucus, stimulated by Progesterone |
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The usefulness of the BOM in helping women to identify
the different stages of her reproductive life cycle has been
clearly demonstrated (3 , 4). The BOM is an invaluable tool
in helping women to identify these conditions through fertility
awareness. As Drs. Billings have stated “self awareness
of fertility and infertility is an important knowledge which
should be available to every woman. The woman who knows her
own mucus patterns will be able to detect a number of gynecological
disorders”.
Questions arise as to when irregularities within the mucus
patterns and the menstrual cycle should be considered abnormal
and when is the point when a woman should be sufficiently
concerned to consult a physician.
The persistence of such factors may increase a woman's risk
of other reproductive system disorders and may be due to serious
metabolic or endocrine abnormalities or to other diseases
all of which need to be recognized.
Menstrual disorders and alteration in the mucus pattern can
be caused by obstetrical, endocrine, gynecologic or iatrogenic
disorders. Early pregnancy complications such as metrorrhagia
and vaginal spotting should be identified by recognizing a
previous fertile phase with a peak day and can be ruled out
with the use of ultra sensitive pregnancy tests and pelvic
ultrasound.
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