You can adjust the sensitivity thresholds by opening the WithBaby app and going to Menu > Set Alert Thresholds. Tap Noise or Motion depending on which threshold you want to adjust.
You can adjust the amount of notifications you get by adjusting the sensitivity threshold and the duration. Moving the slider to the left or to the right will determine the amount of motion or noise needed, over the duration you've selected, before a notification is sent.
Once you've received a notification for a specific event (noise or motion), you won't receive any other notification of the same type for the next 5 minutes. This rule has been implemented to avoid being flooded with several notifications for a same event.