The lessons started in January for expectant mums at the Chelsea and Westminster NHS foundation trust in West London.
Course leaders claim that singing 'can provide emotional, social, educational and physical benefits for women and their babies during pregnancy, labour and after birth'.
The lessons will 'strengthen communication' between mum and baby, and 'prepare for labour through vocal and breathing exercises', whilst building 'musical confidence and repertoire'.
Around 10 mothers-to-be have so far signed up for the free 90-minute classes, which are part-funded by the local authority and the hospital's health charity.
Spokeswoman Anna Matthams, arts assistant for the Chelsea and Westminster's health charity, said: 'Singing is a very early form of communication and expression.
'The baby's auditory system is one of the first things to develop and there's a lot of physiological evidence that singing helps with language development.'
What do you think about this story?
A complete waste of NHS funds?
Or a great way for mums and unborn babies to bond?