Are my babys pregnant

Question
Dear Jessica
  My mum has had cats for aslong as I can remember but I recently moved into my own home with my three cats the two girls came into season after just a week of starting to go out, after a couple of days finished then my male sky went missing (13june) and hasnt returned home yet.
  I have noticed a change in the girls they have got so loving and are always following me around iv asked my mum and she says there not pregnant but i was stroking savanah's bellie last night and fealt a distinct lump and her nipples were out quite abit.  So i felt crystals too although her nipples were normal I couldn't really feel for any lumps as she will not let me near her bellie at all.  Could they be pregnant and are there any other tale tale signs i should be looking for. Thank you very much for your time and help.

Answer
Hi Emma.  Certainly, if they were in heat and were exposed to an unneutered male, then pregnancy is a possibility.  Nature has made it so that just one mating usually results in a pregnancy.

However, the hormonal changes associated with estrus also very often cause the mammary area and teats to swell.  If the kitties were in heat around the 10th of June, then it's too early to tell if they're pregnant with any degree of certainty.  Even a vet would find it very difficult to determine if they were pregnant at this stage.  Usually 4 to 5 weeks along is when pregnancy can certainly be confirmed.

Please keep your girls in and away from unneutered males until they're spayed!  They can get feline AIDS and feline leukemia by the close contact they have with males during the mating process who may be infected (AIDS is spread through bite wounds, and males bite females during mating, leukemia is spread primarily through saliva, either through bite wounds or by swallowing infected saliva during grooming).  I have experience with both diseases.  Both are incurable and both are considered terminal, and both are awful ways to die.