Maternity leave

Mo • Baby boy 💙 12-23-17 Baby girl 💗 05-26-20

I want to work until I can't anymore but my job needs a set date 👎🏾 I understand the baby can come 2 weeks before or after but damn how can I give a set date when it's time the baby will come . Why can't they just start it the day I actually go into labor