1) Even in Muggle society, there are women who work close to their normal capacity despite pregnancy up to shortly before birth.
2) The physiological consequences after birth can probably be healed by magic.
3) Voldemort might also enjoy causing her psychological pain by having her become attached to the child she will bear and then taking it away from her afterwards. He continued torturing her well after he already had her total loyalty, so this might just be another way to do so.
1) Even in Muggle society, there are women who work close to their normal capacity despite pregnancy up to shortly before birth. 2) The physiological consequences after birth can probably be healed by magic. 3) Voldemort might also enjoy causing her psychological pain by having her become attached to the child she will bear and then taking it away from her afterwards. He continued torturing her well after he already had her total loyalty, so this might just be another way to do so.