First of all, let me congratulate you on your pregnancy. That is wonderful news. I am sorry to hear your toxic parents are adding stress to the situation. Unfortunately the rule of thumb seems to be the following: the more joyous the situation, the more toxic these people become.
Let me say this about that turn of phrase ‘the right to see their grandchild’. I think that when they chose to be abusive to you, they forfeited any rights to your children.
Even if the abusive or toxic nature of your childhood was not intentional—but rather circumstantial—you still have to make decision based on the wellbeing of your child. You as a parent are responsible for the people and influences you allow in your child’s life. If you feel that exposing your baby to the toxic influence of you parents is a bad idea, then that is absolutely your choice.
The only way for you parents to potentially influence that decision, is by making real and genuine efforts to improve their relationship with you. Something most toxic people lack the skills or willingness to do.
In order to keep yourself and your child safe, I would make sure that you inform people who spend time with your baby regularly. Like a nanny or babysitter, the school or day care, perhaps even discuss your concerns with your doctor or counselor. At the end of the day, you do not want you parents to show up when your child is in the care of someone else and take advantage. It would also give you some documentation and witnesses if your parents ever go so far to file bogus child abuse charges (we all know these people are capable of such).
In the meantime, try not to worry about it too much. You are No Contact, so you probably have a good set of boundaries and safety measures already in place. Just enjoy the pregnancy and prepare for the start of your very own family.