USG test in pregnancy is a very useful tool to look for baby’s development, multiple pregnancies, anomalies in baby and many other multitudes of things. It is a painless, noninvasive and safe test which can very accurately detect various anomalies in the baby. It uses high-frequency sound waves to study the various internal body structures. These sound waves are sent inside the body via a probe or transducer and then they are reflected back by various tissues in a different manner. These echoes are shown as an image on the screen.
During pregnancy 3-4 USGs are done in various stages of development of the baby. In pregnancy, you do not need to come empty stomach unless specially instructed to do so.
Early viability scan- This is done in early pregnancy to see the site of the pregnancy, number of gestational sacs, the cardiac activity of the fetus, gestational age and various other structures like the ovaries and uterus. By this, we can exactly date the fetus. Ectopic pregnancy can be seen and cause of bleeding during pregnancy can be determined.
NT scan (11-13 weeks) –This is a very special scan done to rule out various syndromes in the baby like Down’s syndrome when the baby is between 45-84 mm in length. It is combined with a blood test for better results. The fluid collection on the back of the neck and nasal bones are seen in this.
Anomaly scan or level 2 scan- It is done between 18-20 weeks to look for the detailed development of various organs of the baby like the brain, spinal cord, heart kidneys, limbs etc. Placenta, ovarian cyst or any other uterine anomaly is also assessed.
Growth scan- This is done after 30 weeks to see the growth of the baby, placenta, amniotic fluid, movements of the baby, blood flow to the baby can be checked and scan repeated according to the results.
It is a very useful diagnostic technique for various anomalies in the baby. But not all 100% anomalies can be detected on USG and if any anomaly is detected, further tests are needed to confirm the same.
What to expect while going through a pregnancy scan?
A pregnancy scan can be of 2 types:
Trans Abdominal Scan (TAS) – Done through the abdomen. Sound waves travel very well in water so you may be told to drink water and hold urine before the scan so that your bladder is full. Bladder forms an effective window through which sound waves travel and organs behind the bladder are well seen. You have to lie on the table, the gel is applied on the abdomen, probe applied and scan done. A little pressure of probe maybe felt and it may take half an hour to be done.
Trans Vaginal Scan (TVS)- This is a better way to look at pelvic organs and baby in the first trimester as the probe is placed inside the vagina near the organs. You have to relax and cooperate. You will be covered by a sheet and a probe covered with a condom and lubricated with gel will be inserted in vagina and scan done. The probe is specially designed for vagina and will not hurt you or the baby.
After the procedure, the gel is wiped clean and you can go to the toilet. It has practically no complications to either you or the baby so you can go for a scan without any worry. If any anomaly is detected, you may be advised to go for further tests like CVS or amniocentesis.
With the advent of 3D and 4D machines, the birth of an anomalous baby has become very rare as anomalies are detected in pregnancy itself and taken care. So you should follow the advice of your doctor and get your scans done on time so that you are saved of any problems later on.