During your pregnancy, your doctor or midwife will measure your baby based on estimates of their size relative to your due date. These values are monitored over time to see the growth of your baby in the womb. Measuring the size of your baby before they are born is not an exact science and cannot be done with 100% accuracy. Based on where your baby’s measurements fall within a spectrum, they could be deemed small (less than the 10th percentile) or large (greater than the 90th percentile) for gestational age. This episode answers a question about changes in growth percentiles over time.