Amniotic Fluid Assessment (AFI) What? This test estimates the amount of fluid surrounding your baby. Amniotic fluid cushions the baby and helps protect the umbilical cord from too much squeezing. Most of the fluid is sterile (clean) urine from the baby. Why? Measuring the fluid around the baby helps your medical team gauge how well the placenta is working. If there is too little fluid, it could be because the placenta is not working well, and baby’s body is compensating. More blood is being directed to the baby’s brain, and less is going to the kidneys and other organs. As a result, the kidneys are producing less urine so there is less fluid. How? This test relies on ultrasound, a technology that uses sound waves to make an image of your baby. The nurse or medical technician will have you lie down on your back and will move the ultrasound transducer over your abdomen. You will be able to see your baby on the monitor as the nurse or technician carefully measures the pockets of fluid that surround the baby. When all areas have been measure, the measurements are added up to give your baby a score called an amniotic fluid index (AFI).