No, there is no tax credit for pregnancy. When your child is born and you prepare a tax return for 2021 NEXT YEAR you can claim your child as a dependent on your tax return.
you can not take a tax credit until the year the baby is born.
The child requires a social security number and that can't be issued without a birth date ; and this has nothing to do with the tax date of April 15.
It has to do with the calendar year. Children born after 12/31/20 cannot be claimed on the 2020 tax return.
Children born in 2021 can be claimed on their parents 2021 tax return which is due on April 15, 2022.