You can still handle your hamster when she is pregnant but be gentle not to put pressure on her belly and it is usually better to not handle her the later she gets in her pregnancy. Clean out her cage about 3 or 4 days before she is dur to give birth. Once she has gave birth you wont know because the mother is NOT to be disturbed as this can cause her to reject the young or even cannibalise them just hold in your curiosity for 2 weeks. By then the babies should be wondering about the cage but don't touch them, the mother will usually pick them up and take them back into bed. After 2 weeks they should still be wondering about the cage so you can quickly pick a few of them up but its better to make sure the mum doesnt mind otherwise if she is very protective she could reject them at 2 weeks. Also make sure she has PLENTY of fresh water as she will get very thirsty in pregnancy and feeding the babies. Some fresh veggies and hard boiled egg can give her extra protein to strengthen her up.
To care for your pregnant hamster you have to be very careful, like if you had a dwarf hamster like me . You may play with her for about an hour or 2 unless if you play to much you can cause hamster murder. Be very careful when you hold her up high above the ground if she bit you would you drop her?what would happen if she crawled over your hands? When the babies are born if rarely they get stuck somewhere you may help them but do not use your hands use a clean spoon
Give your female plenty of water because birth is thirsty work and leave her alone when she gives birth if the mum throws a hamster out of her nest it normally means its dead or rejected also you should start to give it some milk it should be a little sour
Whatever you do do not bother her or the babies for a few weeks after she has given birth. She may eat her young.