If your sub got pregnant, would you want to be the sole decision maker about what to do?
This realistically comes down to consent. There is no ‘right way’ to do Ds, only what the people involved want to do.
If a woman in a 24/7 TPE relationship has agreed for her partner to have that much control over her life and decisions, then she has already excersized her right to make that decision. If she is ordered to do something she feels is wrong she can withdraw that consent.
Pictures by The Pain Files – Pregnant BDSM of Slave A
That said, I think any reasonable human beings would generally discuss something as serious and a baby, and certainly it would be pretty crazy for a Dom to make that kind of decision without talking to the woman involved and taking into account her feelings. At that point, then sure the Dominant partner can make the decision, if that is what the submissive wants to happen, which presumably in a full TPF relationsip would be the case.