Placental lakes

Has anyone ever delt with placental lakes? Long post but i went for a private 4D scan and was told my placenta was “thinning out” so I told my doctor and she immediately sent me for a ultrasound, I seen her after the ultrasound and she said that I have placental lakes and that I am being referred to a specialty dr, I will have weekly ultrasounds, weekly non stress tests, and weekly AFI (amniotic fluid) checks.. I honestly don’t know what any of this means and just trying to see if anyone has had a similar experience.