Ultrasound which is also called as the sonogram, in
pregnancy is an important diagnostic tool which helps the doctor to know about
the development and health of the baby. It is basically a noninvasive test
which sends sound waves to gather reliable information about baby, placenta,
uterus (womb) and other pelvic structures.
Most of the standard pregnancy ultrasound is done between 16
and 20 weeks. However, one can have an early ultrasound at around 6 to 10 weeks
to know the date and confirm pregnancy. The indications for doing an obstetric
ultrasound can be basically divided into three columns- the fetal,
uteroplacental and the maternal status.
The most important fetal cause is first and foremost to
diagnose pregnancy. Other causes include, assessment of growth, well being of the
fetus, and detection of anomaly, diagnosis of ectopic pregnancy, multiple
pregnancies and to confirm fetal viability. Uteroplacental cause includes
detection of any uterine malformations, localization of placenta, assessment of
liquor volume, diagnosis of cervical incompetence.
Maternal cause includes few obstetric intervention such as
amniocentesis, chorionic villus sampling, cordocentesis, and fetoscopy.
The most common kinds of ultrasound include transabdominal
ultrasound, transvaginal ultrasound, 3-D ultrasound, 4-D ultrasound, Doppler
ultrasound. Transabdominal ultrasound is the most common among all. The gel is
spread over the abdomen and a transducer is moved over the thin layer of gel.
In a transvaginal ultrasound, the transducer is introduced through the birth
canal. Both these kinds of ultrasound take about 15 to 20 minutes.
Doppler ultrasound is used to access the blood flow in
umbilical vessels. The transducer is used to listen to baby’s heartbeat.
Doppler is also useful in diagnosing of Rh disease. This is a specific
hemolytic disease in which the mother’s blood group is Rh negative and baby
blood group is Rh positive. This causes the destruction of the fetal red blood
cells and ultimately can lead to death.
3-D ultrasound takes many pictures at a single time and can
be used to access baby’s organs and development. 4-D ultrasound shows baby’s
movement in a video form.
As ultrasound uses sound waves instead of radiation, it is
definitely safer than X-rays. It is good in detecting some specific anomalies
such as spina bifida, chromosomal disorder in which pregnancy needs special
care. A specific pre-hand investigation gives the doctor a chance whether to
continue pregnancy further or to terminate. Ultrasound also tells the position
of the baby in the cervical canal. If it shows the presentation is breech (baby
head is up and feet are facing down in the canal) the doctor first tries some maneuvres
such as external cephalic version to bring back the original position of the
baby. If this manoeuvre fails, the doctor has to go for the cesarean section.
So definitely ultrasound is an important test which not only
helps to diagnose threatening medical conditions beforehand, but also gives the
doctor a chance to take appropriate action and allow continuation of pregnancy
and healthy delivery of the baby.