The more babies a woman is carrying, the more likely it is that her uterus will swell, triggering contractions, says Brian Brost, M.D., associate professor of maternal/fetal medicine at the Mayo Clinic, in Rochester, Minnesota. An early due date isn't the only challenge to having multiples.
Dogs do not menstruate like humans do. Instead, they come into estrus (come into heat/season) about twice a year, once they have reached sexual maturity. This can sometimes be associated with a small amount of blood from the vulva, but it is not truly a period. Female puppies can reach sexual maturity potentially as early as six months old, although the first season (which is the closest equivalent to getting their period) is often at about nine months old.
Once the puppies can see and hear (3-5 weeks), good breeders take the puppies to safe locations to meet new people and expose their puppies to new sights and sounds. Between the ages of 8 and 12 weeks is known as the critical period for socialization.f you are thinking about getting a puppy, read this first. Print it out, carry it in your pocket and when you go visit that litter of puppies, take a deep breath, step outside, and re-read it. If you still want that puppy, at least you have a sense of what your future holds!