my hampster didnt get pregnant

Question
i have tried to breed my syrian hampster and was wondering is it common for her not to become pregnant the first try?  the male and female seemed both very receptive to the mating for approximatly 30-45 mins. so at that time i seperated them. i waited the ten days but she never seemed to "show" at 12 days as a precaution i made sure to clean the cage and leave her as undesturbed as possible but after 18 days she still had not given birth. should i try to mate her again and if so should i try more then once to be sure it is effective? thanks!

Answer
Hi Amanda,

    It is very hard to breed Syrian hamsters, so her not becoming pregnant on the first try does not surprise me.
    Yes you can try to mate her again when she is in season (heat). Leave them together for a hour (as long as they are not fighting). After they have mated, start checking your female every evening for the next 5 days (just to be safe), if she comes back into season then she is not pregnant and you can try mating them again. It she does not come back into season, then she is more than likely pregnant and you can expect the babies in 16 days (counting from the day they mated).
    If you have anymore questions, please write again.

Thank you for writing!