Estimated due date

What it's for

Pregnancy lasts on average about 63 days in dogs and 65 in cats. Knowing the estimated date helps you prepare in time for the birth.

Note

It's an average-based estimate: the real date can vary by a few days. Near term, a vet check is always recommended.

The mating date isn't the conception date

This is why an estimate on 63 days can be well out, and it's worth knowing before marking the calendar. In a bitch, sperm survive up to a week in the female tract, and ovulation can happen days after mating: counting from the day of mating, birth falls in a window between 57 and 72 days, even though the real pregnancy is always about 63 days from conception.

If the date is needed precisely — for a planned caesarean, say, or for an expected litter — the only way is to have the vet establish it: with hormone testing at the time of mating, or with an ultrasound scan, which in the first month gives a far tighter estimate than any calendar sum. In a queen the window is narrower, generally 63-67 days, because ovulation is induced by mating itself.

The signal that birth is close

There's one that can be measured, and it's the most reliable: in the 24 hours before birth body temperature drops by about a degree (from the usual 38.5 °C to 37.5 or less). Anyone expecting a litter takes it twice a day in the last week: it's the way not to be caught out of the house.

The other signals are behavioural and come in the last hours: the animal looks for a sheltered spot and prepares it, refuses food, becomes restless and pants. It's worth having offered the spot a few days earlier — a low box, with something washable inside, in a quiet corner out of the way — otherwise she picks one herself, and it's usually the wardrobe.

When to call the vet, without thinking twice

These are situations where time counts, and knowing them beforehand saves having to judge them at the wrong moment: if strong contractions last more than half an hour with nothing born; if more than two hours pass between one puppy and the next while she keeps straining; if a dark green or foul-smelling discharge appears before the first birth; if the pregnancy goes past 70 days from mating. It's worth having the vet's number and the out-of-hours number written down somewhere before the last week.

Nearby tools

To count the days between two dates there is Difference between dates and to add them Add days to a date. For feeding, which changes a great deal in pregnancy and nursing, there are Dog calorie needs and Cat calorie needs.