Is it possible for my puppy to be in heat at 5 months old? She is a maltipoo with an umbilical hernia, but my vet told me to wait until she was 7 months old to schedule her neutering so she can be big enough to handle to surgery and fix the hernia as well. I think she may be in heat because when I brought her to the dog run, all of the male dogs were attracted to her and jumped her. Could she possibly be pregnant if they were puppies too?