How Do Puppies Get Nourishment in the Womb?

Puppies come into the world much like any other mammal. When a mommy dog and a daddy dog love each other very much, they come together to make a family. Well, maybe it's not as romantic as all that, and pet overpopulation is nothing to make light of, but it's one way to explain how the female dog's eggs and the male dog's sperm come together. The eggs embed themselves in the part of the uterus referred to as the uterine horns, a system called nidation. By day 18, embryo development is firmly underway. By day 22, you can make out the shape of a head and foreleg on an ultrasound.

Each fetal puppy in the litter has her own little sac filled with embryonic fluid and covered with a protective membrane. The embryos are attached to the mother through a rope-like organ called the umbilical cord. It is through this lifeline that the puppy gets the nourishment she needs to grow strong. It is also where the puppy gets her lifeblood and the oxygen she needs to grow a healthy body. Her development continues for 58 to 62 days.

Pregnant dogs should be well fed because everything they eat is being shared with a litter of puppies—not just during pregnancy but also during the eight weeks of lactation afterward. Their diet should be adjusted to include more protein, which the fetuses need to develop strong and healthy muscles. Their calcium and phosphorous intake should be increased because puppies need these nutrients to build strong bones and teeth. DHA is required for a strong nervous system and to develop eyesight. Omega-3 fatty acids are important for healthy bones, while vitamins C and E assist in building a strong immune system.

As the mother dog eats, the calories and nutrients she is ingesting are absorbed into her bloodstream, which she is sharing with her puppies through the umbilical cord stretching between each fetus' sac and her uterine wall. The nutrition delivery method changes so that the nutrients are in the mother's milk after delivery. Once the puppies are born, the umbilical cord shrivels and falls off, leaving a tiny scar that is similar to a human's belly button. Over time the scar disappears, leaving the question: Do dogs have belly buttons? Indeed they do.