some questions about hamster breeding procedures?

They generally won't mate a second time if the first was successful. However they possess the ability to block a pregnancy if she feels that she either cannot provide adequate food and water, or if she isn't healthy enough. This very rarely happens in captivity, most of the time if she does become pregnant she will fend of the male if he gets too close. I have a female syrian who is due within a day or two and she took right away to the male I introduced. They mated on the first day and shared the cage up until today when I removed him just for the night. Sometimes a male will help rear the pups so after I wake up he will go back in there with her. Of course I plan to keep my eye on him, just in case. But, back to your question. If the first attempt was successful then no she will not be able to enter estrus until about 24 hours after the birth, even then it is not advisable to breed her again until the pups are weened and she is back to full health. The closer the pregnancies are the more the risk of issues and ill health problems can be.

Yes she might mate and will be in heat. just like humans that are pregnant and still have sex. they just wont get pregnant until the first litter is gone.

I agree with the other two.