Yeah I got mine at 20 something weeks, its just a slip of paper that states your estimated week of delivery and its signed by your midwife, its just so your employer has proof of pregnancy so you can get your benefit. it also applies even if you lose your baby, as you are still entitled to take the maternety leave if your baby dies after 24 weeks as its classed at this point as still born (sorry for the not so nice information) if you havent got another midwife appointment coming up for a while, you could always give them or your GP a call and ask them to do one and pop it through the door for you or something.