The leaps are based on brain development, which starts at the same time for all babies – the moment of conception. While the period between conception and birth can vary for each baby, the period between conception and the due date is always the same. Therefore, you should normally enter the due date. However, our research has not been conducted on babies born 8 weeks prematurely, and we cannot guarantee its accuracy in such cases.
For more information on the calculation, watch this video: https://www.youtube.com/watch?v=lDc1lEL_oe8
If you feel the app is not working for your baby, we completely understand and are happy to offer a refund.