When Is My Dog Due?
Congratulations, you and your dog are expecting!!
Did you know that depending on what point you count days form an observed mating, your dog's due could be as short as 58 days and as long as 72 days??
How is this possible? A bitch’s heat cycle lasts for about 18-20 days. She is usually only receptive to the male in the last 9 days, but some submissive females may allow breeding at almost any point. Semen from a healthy male can remain alive for up to 11 days in the bitch’s reproductive tract. So.. from the end of her heat and first day of diestrus, it would be 58 days. However, from an observed breeding that occurred at the beginning of her heat cycle, 72 days.
So the most accurate way of determining due date is by the following 3 time points:
1) Due date is 65 days from a luteinizing hormone peak (detected by blood test for LH or interpreted from progesterone)
2) Due date is 63 days from ovulation (interpreted from progesterone)
3) Due date 58 days from the first day of diestrus (determined by vaginal cytology)
All or most of these are determined by your veterinarian by progesterone levels and day 1 of diestrus is determined by looking and comparing vaginal cytology slides from late in her cycle. With one or two time points, the calculation can be very accurate. Without them, even gestational aging by ultrasound and x-rays can have difficulty in narrowing down the due date to less than 3 days. Most puppies do not produce lung surfactant (essential for breeding) until 48 hours before their birth, so accuracy of determination of her due date can make all the difference in their survival.
WE advise that all our female dogs are examined and start ovulation timing once they have been in heat for 4-5 days.
WE start with vaginal cytology to confirm she is far enough into her heat cycle to start measuring progesterone and does not have any signs of inflammation/infection that needs to be treated first.
WE start screening for Brucella canis early into her cycle when we can make critical decisions in the use of the female for breeding.
WE can accurately predict due dates and more easily monitor high risk pregnancies for pre-term labor and safely plan deliveries including elective C-sections.