It is not uncommon for there to be a slight discrepancy between the estimated gestational age based on your last menstrual period (LMP) and the measurement from an ultrasound. Ultrasounds are more accurate in determining gestational age during early pregnancy, so it's possible that your baby is just measuring slightly smaller than expected. In most cases, this small difference is not a cause for concern. However, if there are other factors or abnormalities detected during the ultrasound, your healthcare provider may want to monitor your pregnancy more closely. It's important to discuss any concerns with your doctor or midwife who can provide personalized advice based on your specific situation.