Why a birth time can be reconstructed later
A delivery does not pause for paperwork. In the minutes around birth, a nurse may be helping the parent, assessing the newborn, coordinating with other staff, and keeping track of immediate care. The time of birth is one detail among many, and recording it may wait until the room is calmer. If the nurse then enters the time from memory, the chart reflects a recollection rather than a timestamp captured at the instant of delivery.
A precise-looking entry is not always a precise observation
Charts often ask for a specific time, down to the minute. That format can make an entry look more exact than the process behind it: the recorded time may be precise in format without having been measured in real time. The time a note is entered may also differ from the time of the event it describes.
This does not mean a birth time is necessarily wrong, or that every delivery record is made from memory. It means that when the moment was not recorded as it happened, confidence in the minute depends on how soon it was documented and what the nurse could reliably recall afterward.
