Mum is stuck at 37D
Clue says Premature 6 letters
she has -n--r-
Thought it was going to be unripe but has 'stutter' in for 50A-Stammer- which give the R there.
I wouldn't say unborn is a synonym for premature.
There's also a mistake in 15d soft (in music) is piano - dolce, which looks like the required answer, means 'sweet'