25/01/2023
Excellent information.
Dogs are only pregnant for 63 days. Puppies are not like human babies. There is only a 4 day window when puppies can safely be born.
Timing to schedule a c-section is based on ovulation date, not the breeding date. Puppies can only be born safely 61 to 65 days from ovulation.
Before day 61, puppy’s lungs are immature, lacking surfactant, and if born too early, the pups will gasp a few times and die. These pups often don’t have hair on their faces. In large litters, the mom will often go into labor before day 63. This is usually OK because the pups produce more cortisol when stressed by fetal crowding and their lungs will mature a wee bit earlier than if the litter is a normal size.
On the other end, after day 65 or 66, the placenta fails. Placentas are programed to last 63 days, and can be stretched out to day 66. After day 65 or 66, the placenta will deteriorate and no longer provide the blood flow to the pups necessary to carry oxygen and nutrients. Pups not born by day 66 may die before they are born. Rarely, the females will not go into labor by day 65. If this happens, it is most likely due to a small litter size. Labor in the dog is initiated by the fetuses, not the mother. When there is a small litter, the pups don’t produce enough cortisol collectively to initiate labor in their mother. In these cases, progesterone levels can’t be used to estimate due date. For this reason, we need to know her due date based on progesterone timing at the time of breeding and intervene before it is too late to save pups.
So when you have not done progesterone testing at the front end of the pregnancy, what can you do to time the c-section if you find yourself in need of intervention. Or what can you do to estimate due date if you have a high risk pregnancy?
1. Progesterone timing at the end of pregnancy. A progesterone below 3 ng/dl indicates a c-section is safe, as long as the dog does not have luteal failure. This is most effective when you can get progesterone results back the same day the sample is drawn and sent to the lab. When testing progesterones at the end of pregnancy, we frequently see the progesterone hovering between 3 and 4 ng/ml, sometimes for as many as 10 days. It is NOT safe to do a c-section unless we see the progesterone drop below 3 ng/dl. Don’t be hasty in making a decision based on progesterone drop alone
2. Lactation. If the mother is not producing milk yet, waiting may be a great idea.
3. Ultrasound signs. Puppies that are mature enough to be born have active guts and obvious kidney interior structure. This requires a great ultrasound machine and experience.
4. Maternal behavior. Nesting, refusing food, a temperature drop, and a far-away look in her eye are all indicators of first stage labor.