At my old job, I accrued a few hours of vacation time each month. Since DD was born in January, and my company's policy was that you could only use the vacation you had accrued on your maternity leave. I didn't use any of it when I was on maternity leave, so I still had 3 weeks of vacation to use later that year.
With my new company, they give it to you all at once, so I'll have to use all of it on maternity leave (if I want to get any paid leave), and that leaves me with zero vacation time for the rest of the year