When there is a discrepancy of 8 days between your Last Menstrual Period (LMP) and the date calculated from your ultrasound, it can be confusing to determine which one to use for estimating your due date. In such cases, it is generally recommended to rely on the ultrasound date as it provides a more accurate estimation of gestational age. Ultrasounds are able to measure the size of the fetus and its development, providing a more precise calculation. However, if you have irregular periods or are unsure about the timing of your LMP, discussing this with your healthcare provider is crucial. They will consider various factors such as the reliability of your LMP, the accuracy of the ultrasound measurements, and any other relevant medical information before making a final determination regarding your estimated due date. Remember that every pregnancy is unique, and individual circumstances may vary.