from
the book How to Have a Baby: Overcoming Infertility
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani,
MD.
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Ovulation -- Normal and Abnormal (Page 1)
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Older Woman
Table of Contents
How
is ultrasound used to monitor ovulation ?
How
do I use ovulation prediction kits ( OPK) ?
How
can I use the new pocket microscopes to track
ovulation ?
What
blood tests can be used to predict ovulation ?
What
happens when ovulation is abnormal ?
What
are the blood tests which are used to diagnose problems
with ovulation ?
What
is ovarian failure ?
What
are the treatments are available for inducing ovulation?
How is ultrasound
used to monitor ovulation ?
The egg develops within a follicle in the ovary. This
follicle is a thin-walled structure containing fluid
with the egg attached to the wall. Usually, only one
follicle develops per month. This follicular growth
can be monitored by ultrasound,
usually done with a vaginal probe, which projects an
image of the ovary onto a screen.
The follicle appears
as a circular fluid-filled bubble on the screen, and
can be seen when it is about 7 to 8 mm in size. It grows
at about 1 to 2 mm per day, and is ready for ovulation
when it measures 18 to 25 millimeters in diameter. Following
ovulation, the follicle usually disappears from the
scan picture completely and this is the best evidence
of ovulation.
Often, at the same
time, fluid can also be detected in the abdomen behind
the uterus - this is the follicular fluid which is released
when the follicle ruptures. Defects detectable by ultrasound
are follicles that do not grow at all, or do not grow
to a big enough size, or occasionally follicles that
do not rupture at the appropriate time (luteinised unruptured
follicle).
Since ultrasound
allows assessment of follicular development, it is especially
useful for patients having timed intercourse or having
ovulation regulated with fertility drugs. It is usually
done on a daily basis, from about the 11th day of the
cycle.
Follicle tracking on ultrasound usually
takes about 5 minutes to perform. No preparation is
needed; except that the bladder must be emptied before
the scan. Ask to see the picture of the follicle on
the monitor - and you should be able to see the growth
of the follicle and its rupture for yourself on the
screen.
Older ultrasound machines used abdominal
probes . These require that the patient have a full
bladder, so that the sound waves can reach the ovary.
Not only are they much more uncomfortable for the patient
(who has to sit waiting till the bladder is almost bursting
) but the quality of the pictures is also much poorer
as compared to the vaginal scan.
How do I use
ovulation prediction kits ( OPK) ?
Ovulation prediction test kits (OPK) are available abroad
(or in India at a few chemists) over the counter . If
you live in India, you can also buy them from our online
store. These kits detect LH which is produced
in large quantities shortly before ovulation and can
be found in the urine . Once the LH surge has occurred,
ovulation usually takes place within 12 to 44 hours.
Urine testing is started about two days prior to the
expected day of ovulation and continues until the test
becomes positive. The urine should be collected at the
same time every day - and testing the first morning
urine sample is a good idea.
If your menstrual cycles are irregular,
testing should be timed according to the earliest and
latest possible dates of ovulation. For example, if
your cycle ranges between 27 and 34 days, you could
possibly ovulate between days 13 and 20. Therefore,
testing should begin on day 11 and continue until ovulation
is indicated or through day 20. There is an 80 percent
chance of detecting ovulation with five days of testing
and a 95 percent chance with ten days of testing. Occasionally,
ovulation may not occur in a particular cycle. If the
ovulation prediction test has been timed and performed
accurately and has not turned positive, you should discontinue
testing and begin again with your next menstrual cycle.
Persistent failure of the test to turn positive may
indicate a problem with regard to ovulation.
Once a test has registered positive,
indicating that ovulation is about to take place, it
is no longer necessary to continue testing. Remaining
tests in a kit may be saved and used in the following
menstrual cycle if pregnancy does not occur.
Ovulation prediction kits offer the
advantage that they allow you to predict when ovulation
will occur - thus maximising the chances that intercourse
will be timed at your most fertile period. They can
also be done in the privacy of your own home. However,
they are expensive; and some of the kits have very tedious
and involved testing procedures, so that errors are
not uncommon.
A newer device, The ClearPlan EasyTM
Fertility Monitor, is a palm-sized, electronic system,
that provides information about fertility status by
interpreting the levels of two hormones, estrogen and
luteinizing hormone, in the urine. You need to test
your urine for the presence of these, using dip sticks,
and the information is then input into the system, which
uses it to calculate your fertile days.
How
can I use the new pocket microscopes to track
ovulation ?
Another way of monitoring ovulation uses a pocket microscope,
to check for the phenomenon of "saliva ferning." You
need to let your saliva dry on a glass slide, and then
examine it under the devise, to check for ferning. Prior
to ovulation, the saliva shows the presence of crystallisation
or ferning when it dries, and this suggests that ovulation
will occur soon. Though these devices are now commercially
available, their reliability is still unclear.
What blood
tests can be used to predict ovulation ?
The growing follicle secretes the hormone estradiol
in increasing amounts and its blood level rises rapidly
several days prior to ovulation. If ovulation is being
induced through fertility drugs, estradiol blood tests
may be done on a daily basis in order to determine if
the developing follicles are growing properly. Normally,
the estradiol blood levels should increase rapidly (as
a rule of thumb, they double every 24 hours).
Since the luteinizing hormone (LH) blood
level rises rapidly just before ovulation (this is called
the LH surge), frequent blood samples for measuring
the LH level can also be taken a few days prior to the
anticipated time of ovulation in an attempt to predict
when the follicle is mature and ready for ovulation.
What happens when ovulation
is abnormal ?
Abnormalities of ovulation may appear in several ways.
Menstrual cycles shorter than 21 days or longer than
35 days are often associated with anovulation. In addition,
patients may skip menstrual periods for time intervals
of three months or more and this is called oligomenorrhea
(infrequent periods) . If the periods stop entirely,
this is called amenorrhea.
Many hormonal systems work together
to produce regular menstrual periods, and the blood
levels of the hormones that make up these systems need
to be tested in order to determine the reason for the
ovulatory disorders.
What
are the blood tests which are used to diagnose problems
with ovulation ?
The hormone blood tests, which are usually
done on the third day of your cycle, include:
The FSH level: The FSH level
gives a good idea of the ovarian reserve ( ovarian functional
capacity) - an index of the number of eggs remaining
in the ovaries. A high FSH level suggests that the ovary
has either failed or has started to fail. If the FSH
level is very high (in the menopausal range) then the
diagnosis is ovarian failure. If the level is borderline,
then some doctors will do a clomiphene citrate challenge
test , which allows for an earlier diagnosis of failing
ovaries. Even women with regular menstrual cycles may
have poor egg quality, as reflected by an elevated FSH
levels. This is called oopause. Ovarian
reserve can also be assessed by measuring the levels
of the ovarian hormone inhibin in the blood. Low levels
of inhibin suggest poor ovarian function. However, this
test is still new and is not easily available.
A very low FSH level suggests hypogonadotropic
hypogonadism. This seemingly verbose term simply means
that the ovary in these patients is not working properly
because of inadequate production of FSH by the pituitary
gland. However, in most anovulatory patients, the FSH
level will be in the normal range, and this can be reassuring.
The LH level: This is the other
gonadotropin hormone produced by the pituitary; and
provides much the same information the FSH level does.
Another useful test is the LH:FSH ratio which is normally
1:1. If, however, the LH level is much higher than the
FSH level,this suggests a diagnosis of polycystic ovarian
disease.
Thyroxine and TSH. These test
for thyroid function. The thyroxine level is high in
patients with overactive thyroid glands (hyperthyroidism).
In patients with decreased thyroid function (hypothyroidism),
the TSH level is increased.
Prolactin: Prolactin is a hormone
produced by the pituitary gland that induces lactation
or milk formation.. High prolactin levels (hyperprolactinemia)
can interfere with ovulation . A milky discharge from
the breast nipple , not related to pregnancy or nursing
, is called galactorrhea, and this is a telltale symptom
of high prolactin levels and needs to be investigated.
If the prolactin level is elevated, the doctor will
need to recheck it to confirm it is persistently high.
There are many reasons for an elevated prolactin level,
including certain drugs as well as stress. In some women,
the reason for a high prolactin level can be a small
tumour in the pituitary gland. This is called a prolactinoma
or microadenoma, and the doctor may advise you have
an X-ray of the skull ( or even a CT scan or MRI scan)
to rule out this possibility. However, most infertile
women with hyperprolactinemia can be easily treated
with a medicine called bromocryptine, which is a dopamine
agonist medication . Another medication which can be
used to treat hyperprolactinemia is oral cabergoline,
which is usually taken twice a week. Only if the pituitary
tumour is very large ( microadenoma) is surgical removal
needed, and this is very uncommon.
What
is ovarian failure ?
Ovarian failure is a disease in which the ovaries fail
to produce eggs. This disease is uncommon, occurring
in only about 10% of women whose periods do not occur
at all, a condition called amenorrhea (absence of periods).
Ovarian failure may be genetic (for example, in girls
with Turner's syndrome, a chromosomal disorder) or may
be acquired (for example, following radiation or chemotherapy
for cancers; surgery to remove the ovaries for treating
ovarian cancer or severe endometriosis; autoimmune ovarian
failure; or for unexplained reasons.) Ovarian failure
is diagnosed by finding a high FSH level. In such patients
it is usually not possible to stimulate ovulation and
they have any eggs, and they suffer a premature menopause.
The only effective medical treatment for these patients
is the use of donor egg IVF
. However, in a very small proportion of these patients,
ovulation can resume spontaneously.
What
are the treatments are available for inducing ovulation?
What forms of treatments are available for inducing
ovulation?
The most commonly prescribed medicines
for induction of ovulation include the following: clomiphene
citrate, human menopausal gonadotrophin (HMG) and follicle
stimulating hormone (FSH), HCG (human chorionic gonadotropin),
bromocriptine, GnRH (gonadotropin releasing hormone)
and GnRH analogue.
For women with hypogonadotropic hypogonadism
(low FSH and LH levels), the treatment of first choice
is HMG. This is effective replacement therapy; and excellent
pregnancy rates can be achieved in these women.
For women affected by hyperprolactinemia,
the drug of first choice is bromocriptine.
For most other women, the drug of first
choice is clomiphene - the "workhorse" of ovulation
induction. If this does not work, then HMG is resorted
to.
Poor responders to HMG can be treated
with GnRH analogues in conjunction with the HMG; or
by adding a hormone called the human growth hormone.(HGH).
HCG (human chorionic gonadotropin) is
given to trigger off the release of the egg.
In patients with high androgen levels
(high blood levels of male hormones), dexamethasone
can be used as an adjunct, since this suppresses androgen
production.
You can read more about these medicines
and how they are used
in the Chapter on Understanding
Your Medicines.
Often ovulation induction requires an
investment of time, money, energy and emotion before
a satisfactory response is achieved. After all, every
woman is different and there can be no standard "formulae".
Careful monitoring of the response to ovulation induction
is the key to therapy - and this usually involves daily
ultrasound scans and/or blood tests. It is often a tedious
process - which may involve "trial and error" to tailor
the therapy to the individual patient's ovulatory response.
With the treatments available today, however, correcting
ovulatory dysfunction is one of the most rewarding and
successful of infertility treatments.
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Older Woman
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Ovulation -- Normal and Abnormal (Page 1)
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