More Info (continued):
If your mother hamster is ignoring her babies, you don�t have to worry right away. She will leave the nest for periods of time but should return to nurse the babies. If a female totally abandons her litter, you may need to try fostering them with another female hamster or hand rearing them. It may be next to impossible to hand-rear a baby hamster that is less than ten days old, and fostering can be difficult before fourteen days of age.
Syrian hamsters have a gestation period of approximately sixteen days. Dwarf hamsters have a slightly longer gestation period -- approximately twenty days.
You can remove the babies from Mom when they are about a month old. Yes, hamsters grow fast! If you possibly can, try to separate the boys from the girls. Hamsters are a very precocious species. This is, of course, easier said than done. If a pet shop or someone will take the whole litter, you won't need to bother sexing them. Just take the whole lot to the shop. Being sad at this time is normal. But reassure yourself that you are doing what's best for them, for you and for Mommy Hamster.
Source(s):
http://answers.yahoo.com/question/index?qid=20 070523154602AA0JdlM
http://hubpages.com/hub/Help__My_Hamster_Is_Pr egnant