Personally I hate the line of thinking that mother carried them so therefore has more rights when it comes to naming. Parents are equals. Unless something is going dreadfully wrong in a relationship (domestic violence, an affair etc), you are a partnership and need to have a sensible adult conversation in order to come to a joint decision you can both agree on. What about women who can't carry their own babies? Are they not as worthy of the honour of naming their babies because they didn't carry and birth them? Is it only mums who can carry and birth their own babies whose rights apparently trump the father? It makes no sense. Fathers cannot carry a child, it's not simply that they're choosing not to!! Someone above uses the idea of babies not being property as an argument for why mother who carried them apparently has more naming rights than father. You are right, they are NOT property, therefore it's rather arrogant to use that line to claim YOU should have more rights to name them simply for being biologically fortunate to be the one who carried them.
Ok, general rant over and back to the OP in question. I'm clearly guessing there is vital information you are choosing not to share with us as to why you are deciding to do things so differently with this baby compared to your older ones (assuming your husband is actually the biological father of all if them?). If he is not the father of this one and knows he is not, do not name him as the father on the bc. It will only cause major trust issues between you and your unborn child further down the line if you lie to them. If he is the father, you should think long and hard about the legal consequences of going behind his back and not naming him so on such an important document. That is a MAJOR decision with huge ramifications for the future of your relationship so I would think very carefully before taking such drastic action, whatever is going on in your relationship. To he honest, I'd say that would be pretty marriage ending if you failed to name him on the birth certificate at all.
If you are not safe, you need to get yourself and your other children out of there pronto and seek legal advice. I understand that is an incredibly difficult thing to do but there are women's refuges and charities who can support you.
If you are safe and your husband is the father I'm afraid I find your decision seems quite selfish. You are thinking about what you want, rather than what is best for the family and your children. Wanting baby to have your surname is completely reasonable but should really be a decision you make (together) when you start having children together. Once you have more than one, you are all part of a family and everybody's feelings should be considered. What kind of message does it send to your older children if you give this baby a different surnamd? That they are less important to you than this child? That they are different in some way to this baby? Children having different surnames to one of their parents is not at all unusual, but giving children with the same biological parents different surnames to each other definitely would be. The justification of "I carried them" doesn't really wash if you made a different decision with the older ones as how do you explain your decision to them? Try thinking of this from their perspective. I would either change their names too, if there are generally major irreparable issues in your marriage making you feel ou need to make this choice this time, or keep this baby's the same as it's older siblings in order to treat them the same.
Sorry if that sounds harsh but, unless there's something majorly unhealthy going on here which you've chosen not to tell us, I feel you've committed to using your husband's surname now for the older ones so that's a decision you should stick with for all your children with him, for fairness. Unless your husband is not the father or has committed an offence making him not worthy of the title anymore, you do not have more right to name your children simply because you carried them. You are equals and should make joint decisions as so. Never ever leave a biological father off of the birth certificate unless you have good reason to. Your child is not some sort of pawn in your power games as a couple. As others have said, through being your husband he would have parental responsibility regardless of whether you name him on the birth certificate anyway. A birth certificate is a legal document. Whilst you can technically choose any name you like for your child, you can't pick and choose what information you put on there. It's a legal document. If he is biological the father he should be named as so.