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INVESTIGATIONS
AND TESTS
INTRODUCTION
During pregnancy profound
changes occur in your body. Every aspect of your
body shows marked changes.In a healthy lady these
changes are easily accommodated in her body without
really dipping into her reserves. For those who
start pregnancy with a physical or medical problems
the body will put pressure on these limited reserves.
As a result there will be evidence of adverse effects
on the body.Your doctor’s job is to assess the state
of your body and among the measurements that will
be done is to have your blood and urine examined.
Both these investigations can give clues as to the
state of your body as it adapts to your growing
pregnancy.
The doctor will ask for common laboratory tests
during your pregnancy by drawing some blood from
your arm and obtain a urine sample.
Pregnancy places a heavy load
on the urinary tract ,cardiovascular(heart andblood
vessels),respiratory systems, which is easily adapted
by most women. Hence it is very important to ensure
that these systems are functioning normally before
the start of your pregnancy.
Urine is excreted by your urinary tract. The urinary
tract comprises of the following:
- Urine
test (Urine analysis)
The
urine comprises the end products of your body’s
metabolism, which is filtered out in the kidneys
and excreted through the ‘water works’ to the outside.
Hence if there is any damage to any or both of the
kidneys, these end products would accumulate in
the body causing undesirable effects. The kidneys
could also be damaged due to infection from bacteria
causing inefficient functioning. Also the collecting
tubes or the bladder may be damaged or blocked,
or damaged due to infection.
In the clinic when you are given a jar and told
to pass urine in it, to ensure a ‘clean catch’ it
is advisable to first wash yourself, pass a little
urine in the toilet and then pass urine in the jar-
a midstream specimen.
Urine will be tested for Confirming
Pregnancy (hCG hormone)
Protein
Sugar
Bacteria.
pus cells
The
routine blood tests that are done are:-
- Test for confirming pregnancy (hCG assay)
- Hemoglobin content
- Complete Blood Count
- Blood Group and Rh factor
- VDRL Tests for syphillis (sexually transmitted
disease)
- HIV Factor for AIDS
- Hepatitis B Screening.
- Blood sugar at 24-28 weeks.
If
there is a family history of diabetes or if you
are over weight or if your growing baby is assesed
to be larger than expected, there is a chance of
developing gestational diabetis.
Ultrasound was adapted to medical use in the early
1960's when it was first used in Obstetrics to locate
the position of the foetus and the placenta or afterbirth.
Today, because of advances
made in instruments, it is possible to learn important
information about the foetus and its surroundings.
Purpose
of test
The common reasons of asking for a Ultrasound are
:-
- Confirm an early pregnancy. .
- Rule out ectopic pregnancy. This is usually
necessary in early pregnancy.
- Determine due date.
- Determine foetal position.
- Identify location of the placenta
- Verify the diagnosis of twins/multiple pregnancy.
- Evaluate foetal growth.
- Determine the amount of amniotic fluid around
the baby.
- Assess fetal well-being.
- Accompaniment to special procedures.
The test is normally performed in the doctor’s
clinic or a hospital.In India the test is usually
done by a Doctor who is a specialist in Radiology
or is also done by the Obstetrician.
There are no risks or precautions to be taken.A
commonly asked question is if the procedure of ultrasound
harms the baby. Thus far, from all the information
gathered and studied in human beings, there has
been no good data published that indicate that ultrasound
used during obstetrical diagnosis has any ill effect
on the growth and development of the baby.
Trans
Abdominal
Procedure
The test requires a full bladder
to help define pelvic organs. Drink several glasses
of water about 1 hour before the test. Do not urinate
until the test is finished.
Follow the doctor’s instructions for positioning
your body. Oil or jelly is applied to your abdomen
to improve sound wave transmission. The doctor guides
a transducer, which may feel cold on your skin,
over the area examined. Transducer sends an ultrasound
beam, composed of very high-frequency sound wave,
inaudible to the human ear. Ultrasound waves travel
at varying speeds, depending on the thickness of
the material they travel through. After passing
through the tissue, reflected sound waves are converted
into electrical impulses and displayed on a video
screen for interpretation or photographing for later
interpretation.
Abdominal
USG(Ultrasound; Sonogram)
You will want to urinate
as soon as the test is finished. The time before
results are reported to patient varies from a few
minutes to a few days.
Trans-vaginal
In
certain cases, an internal ultrasound may be required,
particularly in early pregnancy. This is called
‘trans-vaginal sonography’ and can define pelvic
structures and early pregnancy better, as it is
done by a probe placed inside the vagina (like an
internal examination with a picture of your inner
organs being taken). Your doctor will specify if
such procedure is necessary. A full bladder is not
required for this procedure. pic of trans vaginalUSG
The ultrasound can be used to calculate the due
date of delivery. This is particularly helpful when
the exact date of the last menstrual period is not
known or if the periods have been very irregular.
The parts used in the measurement are the bi-parietal
diameter of the baby’s head, the length of the femur
and the circumference of the abdomen. The accuracy
of the procedure can determine within one to one
and a half weeks of pregnancy.
It is possible to determine the sex of the baby.
This is possible with the machine getting sophisticated.
If the foetal position permits visualization of
the genital area, it has been possible to make a
guess of the sex of the baby. You will not be told
the sex of your baby unless you want to know. Sometimes,
under certain conditions it is necessary to find
the sex of the baby, especially with a genetic inherited
condition. If that is the case, then a effort would
be made to identify the sex. Although ultrasound
is able to identify many abnormalities, so-called
"normal" results do not guarantee that your foetus
is without abnormalities.
Rubella
Test
Done
for German Measles-(Rubella). If there is history
of exposure to an infected individual, ideally,
rubella status should be determined prior to getting
pregnant – if not immune, you should be immunized.
Most people are immunized in childhood now by MMR
vaccine.
Blood test for
Alpha feto- protein (AFP)
This test can be done on mother’s blood
(MSAFP or Maternal Serum AFP) around the 14th
– 16th week of pregnancy. It is a screening
test i.e. an abnormal result is found in certain
conditions. High levels make the doctor suspect
defects in the development of spinal cord or brain
(neural tube defects) in the baby.Gastrointestinal
tract or in kidneys (congenital nephrosis) Low levels
may be seen in genetic defects such as Down syndrome.
An abnormal result needs to be verified by additional
tests, which will be advised by your doctor. MSAFP
is not done for all pregnancies. The doctor usually
will suggest it to you if it is necessary.This blood
test is done when there is a suspicion of a Neural
Tube Defect in the unborn baby- Spina bifida, anencephaly.
Triple
Marker Test
This specialized
test may be recommended if you or your doctor is
worried that the baby may not have developed normally.
It tests a pregnant woman’s blood around 14 – 16
weeks for AFP (as above) hCG (human chronic gonadotrophin),
and estiol.
A computerized program will give your risk,
taking into account variables like your age, medical
history and other factors. This new test is not
yet available everywhere but is being done by some
centers. If abnormal detailed testing may be recommended
by your doctor.
Invasive
Tests for Special Cases
In certain cases when screening tests like AFP
or Triple Marker are abnormal, or there is a past
history of child with genetic defects (haemophilia,
thalessemia, Down’s, sickle cell major, cystic fibrosis
etc) it may be necessary to take out some foetal
tissue for genetic testing. This may be done by:
This
test is done around 16 weeks,but may be done earlier
or later in special cases.This is a procedure where
under the guidance of an ultrasound a needle is
passed into the uterine cavity and some amniotic
fluid is sucked out. This test is done on suspicion
of genetic defects.For details of special tests
your doctor is the right person to guide you.
A test done in early
pregnancy. The procedure involves inserting a needle
into the uterus cavity into the placental site to
suck out a very small bit of tissue. This test is
done to determine certain genetic disorders like
Tay -Sach’s Disease, Sickle Cell Anemia. Thalassemia,
Down’s Syndrome. The risk involved in this procedure
is risk of abortion and damage to fetal limb.
- Tests
for your baby's health in-Uterus
These
are usually recommended in advanced pregnancy (after
32 weeks) and are to be done if your doctor advices
it.
- Daily
Foetal Movement Count (DFMC)
Changes in fetal movement may reflect changes in
fetal well-being. By keeping a record of the number
of times your baby moves during the day, you can
provide useful information on fetal well-being.
Some babies are more active than others.
There are various methods to evaluate the movement
count. The easiest way is during the evening hours
to record the time that has elapsed to feel the
baby kick 10 times. The average time taken to feel
10 movements is 21 minutes. If you have taken 2
hours or more to feel 10 movements, contact your
doctor.
This
is a test to assess the well being of your baby.
It is a non- invasive test and carries no risk of
the procedure. The duration of the test is approximately
20 minutes.
In this test , movements of the baby are monitored
along with the heart rate with each movement. The
baby needs to be awake during this test.
With the movement of the baby, there is a corresponding
increase in the heart rate.
The NST is done in a high risk pregnancy and is
usually done after the 36 th week and repeated weekly.
In
late pregnancy, to assess the baby’s health in utero,
the gynecologist studies the foetus to know the
movements, posture and one, and assesses the placenta
and amniotic fluid. The overall result tells you
how well the baby is doing. If the result is not
good, further tests or some intercention may be
needed. Some intercention may be needed. This is
usually done if there is some problem complicating
the pregnancy, such as hypertension, diabetes, IUGR,
etc.
Cartoon of a dr. using
a doppler
This is a special addition
to the routine ultrasound machine, which enables
study of blood flow to the baby and in the feto-placental
circulation. It is done to assess feotal health
in complicated pregnancies, and may be used in deciding
when to deliver the baby.
- Vitro-acoustic
stimulation test (VAST)
Here
a vibrating and sound stimulation is given through
the mother’s abdomen to the foetus and its reaction
in terms of increase in heart rate and movements
is seen
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Tests
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