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Lakeland, FL
A 22-year-old female asked:

Taking into consideration an us is -/+ 2 weeks in 2nd trimester, what is the cause of this? does it mean the fetus is growing at a faster rate?

1 doctor answer1 doctor weighed in
Dr. Jeff Livingston
Obstetrics and Gynecology 23 years experience
Margin of error: Any technology has a mathematical margin of error. A sonogram is not different. As the pregnancy progresses you also have to account for individual fetal growth variations. The fetal measurements are used to calculate the approximate gestational age. The earlier the more accurate.
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Last updated May 27, 2013


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