Does an employee who wishes to exercise their right to statutory maternity leave have to give their employer all the required information at the same time?

To take statutory maternity leave an employee must advise their employer of their pregnancy, the date on which they wish to commence maternity leave, and the expected week of childbirth (EWC), all by the end of the 15th week before the EWC. However, they are not required to provide all this information at the same time. Health and safety guidelines advise that employers should encourage employees to provide them with notification of pregnancy as soon as possible so that health and safety protection begins to apply.