Phases of the Dog Embryo & Fetus Fertilization - 96 hrs.
Divides into two cells - 120 hrs.
Divides into four cells - 144 hrs.
Divides into eight cells - 192 hrs.
The morula is constituted - 9 days
The morula installs itself in the uterus - 15 days
A blastocyte is formed, which is still floating around freely in the uterus - 18 days
The placentas are developed - 20 days
The ovules have changed in shape in order to become embryos that adhere to the walls of the uterine horns; the nervous system is already formed - 28 days
The embryos are already oval shaped & measure approx. 14-18 mm - 30 days
The sexual characteristics are already present and the eyes are covered by the eyelids - 40 days
The abdominal swelling is already noticeable in the mother, especially if there is a considerable number of puppies - 45 days
From this moment on, the growth of the fetus is very fast - 51 days
The bones of the fetuses are already calcified and therefore can be seen by means of x-rays in order to verify their positioning and approximate number - 57 days
The fetuses have already completed their prenatal development and are ready to be born. From the 58th day on, whelping is imminent
| 
