Puppy development - First month

Topaz has completed the first month of gestation. In my posts about Phoenix's gestation, I've referred to the first, second, and third "trimester," to relate the 9-week canine pregnancy with the 9-month human one. However, with dogs the scientists and doctors actually tend to divide the gestation period into two parts of about a month each.

The first month is embryonic development. This covers fertilization, implantation of the morule in the uterine wall, and the initial stages of development before the embryo starts to really take the form of a dog. In this early stage, the nervous system is formed (brain, spinal corn, nerves). The basic shape changes from round to elongated, with a head-bump at one end and a narrow body-tail at the other. By the end of the first month the embryos are about 14-18mm in length. Up until this time the embryos are still somewhat susceptible to malformation and resorption by the mother's body.

Puppy embryo

 Changes in the dam are generally limited to fussy eating and perhaps some intensified affection or possibly moodiness. Physical changes (belly swelling or mammary gland development) are not noticeable yet.