Maternal mortality is a big word that means when a mommy dies while she's having a baby, or shortly after.
Sometimes mommies get very sick during pregnancy or childbirth and they can't get the help they need, which can make them very, very sick or even die.
Maternal mortality is a problem all around the world, but it's especially bad in some countries where mommies don't have access to good healthcare or where it's hard to get to a hospital.
Doctors and nurses are working very hard to make sure mommies get the help they need, so that more mommies can stay healthy and have babies safely.