Ultrasound technicians typically use a standard measurement for growth. While there are a few available formulas for this measurement, most use the Abdominal Circumference measurement as part of the calculation. In a baby with gastroschisis, this measurement is not the same as it would be if the intestines were enclosed in the abdomen. While many gastroschisis babies are intra-unterine growth restricted (or IUGR) for various factors, this is true for roughly half of gastroschisis pregnancies. Studies show that traditional measurements tend to underestimate the weight of a gastroschisis baby in utero.6 Please consult with your doctor for alternative measurement options, and ask about the Siemer formula, which has been shown to be most accurate in determining the weight of a fetus with an abdominal wall defect in utero.7,8

6. http://www.jultrasoundmed.org/content/31/11/1753.full.pdf

7. http://onlinelibrary.wiley.com/doi/10.1002/uog.5294/pdf

8. http://www.jultrasoundmed.org/content/29/7/1069.full.pdf