USG Scan - Amniotic Fluid Index (Twins) Test

As compared to singleton pregnancies, twin pregnancies have increased risk as there is a danger of spontaneous abortions, malformations, low birth weight and preterm deliveries. There are many other additional difficulties including gestational diabetes, hypertension, acute fatty liver and placental abruption. These are few pregnancy complications which makes twin pregnancies significantly higher at risks than the singleton pregnancies. In both the cases, an amniotic fluid volume can be measured accurately but there are different techniques used for measuring the amniotic fluid. And in the twin pregnancies case, USG scan is preferred for measuring the amniotic fluid index.

There is no special preparation needed before going to the USG scan test unless advised by the physician or the doctor. And there is no need to alter anything in the diet of the patient and can remain stick to their primary food chart. No fasting is needed to be done on the day of the scan by the patient and there is no mandatory dress or uniform needed during the scanning. The scan is basically for the measurement of amniotic fluid volumes which varies with gestational age. The amniotic level of 8-18 cm is considered normal. The level less than 5 cm is considered as oligohydramnios and level between 20-24 cm is considered as polyhydramnios.

An ultrasound scan is a medical test which uses high-frequency sound waves to capture live images from the inside of patient’s body, it is also known as sonography. An ultrasound or USG scan can be ordered by the doctor when you are having pain, swelling or other symptoms which requires an internal view of the organs. In certain medical procedures such as biopsies, a USG scan is a helpful guide to surgeon movements.

To determine the amniotic fluid volume in twin pregnancies, a number of techniques are used
while USG scan is considered the most accurate and useful. The procedure for carrying out USG
scan for measuring amniotic fluid level is as follows:
• Step 1- The transducer is held perpendicular to the floor.
• Step 2- The uterus is divided into four quadrants using the lines nigra as the vertical line.
• Step 3- The amniotic fluid index applied to a twin gestation, does not take into account the
membrane placement.
• Step 4- The amniotic fluid index method applied to twins poorly detects fluid discordance
since it does not take into account the membrane placement.