Well, I think the premises are faulty in the first place because we're talking about the natural mammalian reproductive cycle. It's not as if the baby is just some parasitic invader, it's her developing child. What are you are calling risks are really possible medical complications which could happen but aren't likely and you try to minimize those so you have a healthy pregnancy. It's not unlike trying to maintain your health in general, except now it's two people instead of one.
But that aside, I suppose you could say a born baby also poses some sort of "risk" and "expense" for the mother, like psychological risk (post-partum depression and post-partum psychosis, for example) and financial expense. But it depends on how you define risk and expense.