Dog Pregnancy Week by Week: Timeline and Calendar

By Marcos Ortega · Updated October 25, 2026 · Runs in your browser; nothing you type is sent anywhere.

Educational estimate, not veterinary advice. These numbers come from published averages and can be wrong for your pet. Your veterinarian, who can examine your dog or cat, is the right person to decide what is healthy for them.

A dog’s pregnancy lasts about nine weeks. Not much shows at first, but there are clear points when a vet can confirm it, count the puppies and get ready for the birth. Enter the breeding date (or the LH surge date from your vet’s tests) to see those milestones as dates. For the due date alone, use the dog pregnancy calculator.

Week by week

Day counts are the Merck Veterinary Manual’s days of gestation. Counted from a breeding date, any of them can be several days off.

Week	Days	What happens
1–2	0–13	Breeding and fertilization. Nothing to see or test yet.
3	14–20	Embryos implant in the uterus at about day 18. Ultrasound before day 21 can miss a pregnancy.
4	21–27	A vet may feel small swellings in the uterus from about day 21. A relaxin blood test works after about day 22–27. Ultrasound from day 25.
5	28–34	Best window for ultrasound (days 25–35). The skeletons start to calcify around day 28, but don’t show on X-ray yet.
6	35–41	After day 35–38 the swellings are harder to feel.
7	42–48	Skeletons show on X-rays from about day 42–45, clearly by day 47–48.
8	49–55	Getting close. Plan the whelping area and your vet’s emergency number.
9	56 onward	Best time for an X-ray to count puppies: after day 55. Due: 64–66 days after the LH surge, 58–72 days after the first breeding.

Labor, in Merck’s numbers

Sign or stage	What’s normal
Temperature drop	to 98.1–100°F (36.7–37.8°C), 8–24 hours before whelping in most dogs
Stage I (cervix dilates)	12–24 hours
Stage II (puppies born)	Intervals of 30–60 minutes between puppies are typical; efforts shouldn’t last more than 1–2 hours between puppies. Ideally done in about 7–9 hours
Stage III	Delivery of the placenta

Call your vet if labor doesn’t start by the end of the due window, stage I goes on longer than 24 hours without straining, she strains for 1–2 hours without producing a puppy, she or the puppies seem distressed, or the delivery isn’t finished within 4–9 hours (Merck’s signs of dystocia).

Worked example

First breeding on November 2, 2026. Implantation: about Fri, Nov 20, 2026. Ultrasound window: Fri, Nov 27, 2026 – Mon, Dec 7, 2026. Skeletons on X-ray from Mon, Dec 14, 2026 – Thu, Dec 17, 2026; best X-ray to count puppies after Sun, Dec 27, 2026. Due window: Wed, Dec 30, 2026 – Wed, Jan 13, 2027.

Limitations

A breeding date is imprecise. Conception doesn’t happen on the day of mating, so milestones counted from it can be early or late. Progesterone timing at your vet narrows everything down.
Not a care plan. Nutrition, exercise, deworming and vaccinations during pregnancy are for your vet to advise. Our food calculators deliberately leave pregnancy out.
Every litter is different. The ranges are typical values, not rules.

Frequently asked questions

How early can a vet confirm a dog's pregnancy?

Per the Merck Veterinary Manual, a vet may feel small swellings in the uterus from about day 21, a relaxin blood test works after about day 22–27, and ultrasound is best at 25–35 days (before day 21 it can miss a pregnancy).

When can you count the puppies?

On X-rays, once the skeletons are visible: from about day 42–45, clearly by day 47–48. Merck says an X-ray after day 55 is the best way to count the litter.

How long is a dog pregnant?

Merck gives 64–66 days from the LH surge, 56–58 days from the first day of diestrus, and 58–72 days from the first day she accepted breeding.

What are the signs that labor is near?

Merck notes that most dogs have a drop in rectal temperature to 98.1–100°F (36.7–37.8°C) 8–24 hours before whelping. The first stage of labor, while the cervix dilates, normally lasts 12–24 hours.

When should I call the vet during whelping?

Merck lists these signs of a difficult birth: labor doesn't start at term; the first stage lasts more than 24 hours without straining; strong straining for 1–2 hours without a puppy; signs of distress in the mother or puppies; weak or stillborn puppies; or delivery not finished in a reasonable time (within 4–9 hours). Agree a plan with your vet before the due date.