I don't think the stone table ritual was sufficient for that due to being an out-of-body experience for him, but I suppose Mab could always force Harry to repeat it physically if she wanted to.
So it's theoretically possible, but unlikely to happen from a story perspective. Harry is busy enough with the kids that he has, and I doubt that Mab has any interest in carrying our Friendly neighborhood Wizards spawn to term- she's got him firmly under thumb already, no need to take a baby hostage as extra leverage for now.