Estimated Fetal Weight (EFW)
What is estimated fetal weight?
Fetal ultrasound measurements show how the baby is growing and also help detect abnormalities. The estimation of the fetal weight during pregnancy is among the most important examinations done. These measurements may help your doctor determine whether the baby is too small (intrauterine growth restriction: IUGR) or too big (large for gestational age: LGA). Babies that are too small or too large have higher risks of complications. Because the early detection of growth abnormalities may help to manage complications more appropriately even before the baby is born, monitoring fetal growth is an important part of antepartum care. Monitoring can be done through several steps including palpating the uterus and the fetus, measuring the size of the uterus, and performing a sonogram. A sonogram will measure various parts of the fetus, including the head, abdomen, and upper thighbone.
The growth of the fetus (and the percentile of the ultrasound sonogram) during pregnancy is dependent on many factors such as genetic, placental and maternal factors. Under normal circumstances, the fetus' inherent growth potential yields a newborn of appropriate size (not too big or too small) with a wide range of ‘normal’ sizes. The maternal-placental-fetal units act in harmony to provide the needs of the fetus while supporting the physiologic changes of the mother. When there is a limitation of growth potential in a fetus, that is comparable to failure to thrive in the infant. The causes of both can be intrinsic or environmental. The key is to detect any growth issues as early as possible.
