It is not uncommon for there to be a discrepancy between your estimated gestational age based on your own calculations and the measurements obtained during a scan. In such cases, it is generally recommended to rely on the ultrasound scan as it provides more accurate information about the development of your baby.
Ultrasound scans are considered more reliable in determining gestational age because they measure specific fetal growth markers. However, it's important to note that even ultrasound measurements can have a margin of error, typically around 1-2 weeks.
If there is a significant difference between your estimated gestational age and what was revealed in the scan, you may want to discuss this with your healthcare provider. They can review both sets of data and provide further guidance based on their expertise.
It's also worth considering that variations in menstrual cycle length or irregular ovulation can sometimes lead to discrepancies between estimated due dates and ultrasound measurements. Your healthcare provider will take these factors into account when assessing your pregnancy progress.
In conclusion, while it can be confusing to have conflicting pregnancy calculations from an app and an ultrasound scan, it is generally recommended to follow the information provided by the medical professionals conducting the scan. They will consider various factors and provide you with the most accurate assessment of your gestational age.