It's best that you send your wife back home before she gives birth because it will never work out. Same thing happened to me. I ended up being deported with my baby. Before she leaves, she has to submit a letter to the authorities signed by her sponsor, to cancel the maid visa.

Once she has the baby, get their passport copies and apply for a family visa. If you really need to bring them back, bring them on a family visit visa. But just to be sure, go for the permanent family visa so you won't face troubles of being rejected again and again at the Labour Office before bringing them back.