The gestation period of Syrian hamsters is 16 days and so the female will normally give birth 16 days after the date of successful mating. Very occasionally a female may not give birth until the 17th or 18th day. The female will usually start to show pregnancy at around 10 days after mating. Her abdomen will become swollen and the nipples will become more prominent. During pregnancy high protein foods such as scrambled or boiled egg, wheatgerm, cheese and tofu will be beneficial. Handling the female can continue until a few days before the pregnancy when this is best kept to a minimum. It is also a good idea to remove the wheel a few days before the birth and whilst the mother is nursing the babies. The cage should be cleaned out two days before the expected litter is due and the female should be given plenty of suitable bedding. The female should be disturbed as little as possible around the time of the expected birth.

If a pregnant female does not give birth after 18 days this is usually an indication of phantom pregnancy, labour not occurring or problems giving birth. It is possible for a vet to induce pregnancy but this is very difficult and most vets would not be willing to attempt this. If the female does not show signs of giving birth this is normally not a great worry as the babies will be re-absorbed into the bloodstream causing no harm to the female. However, if a female seems to be having difficulty giving birth or seems sick then veterinary advice should be sought immediately.