Apologies for the delay in replying – it took a little while to find the answer.
This is a very good question.
WHO started a few weeks ago a living systematic review on pregnancy and COVID-19, including MTCT.
https://www.birmingham.ac.uk/research/who-collaborating-centre/pregcov/index.aspx
So far, the evidence suggest there is no confirmed cases of MTCT. A small proportion of newborns present symptoms close to birth, some may have positive test without symptoms. Most of the cases seem to be horizontal transmission after birth.
As long as the infant is well birth dose vaccination can be given.