How long are dogs pregnant? 63 days, week by week

Dogs are pregnant for about 63 days — nine weeks. Measured from ovulation, that figure is remarkably consistent, within a day or so. Measured from the mating date, which is what most owners actually have, the same pregnancy can appear to last anywhere from 57 to 72 days.

The pregnancy calculator turns a mating date into a due date with that range, and dates the milestones along the way. This post is about why the range is so wide, what happens each week, and what to have ready before day 63.

Why mating date gives a two-week window

Sperm survive in the female’s reproductive tract for up to about a week, and a female dog will often accept a mating for several days either side of ovulation. So a mating on a given day can fertilize eggs released anywhere from a day or two later to nearly a week later. The pregnancy clock starts at ovulation, not at mating.

That is the whole explanation. The pregnancy itself is not variable; the starting point is. The standard reference figures are:

due date     = mating date + 63 days
normal range = mating date + 57 to 72 days

If a vet has timed ovulation with progesterone testing — routine in planned breedings — the due date can be pinned down to about 63 days after ovulation, give or take a day. If not, plan around the range.

Week by week

Weeks 1–2 (days 1–14). Fertilization and early development. Nothing to see, nothing to do differently. Feed and exercise as normal.

Week 3 (from about day 18). Embryos implant in the uterus. Some female dogs go off their food for a few days around now; some show mild nausea. Neither is a concern on its own.

Week 4 (from day 25). Pregnancy can be confirmed by ultrasound, which also shows heartbeats. Ultrasound is unreliable for counting puppies, so do not take the number too seriously.

Week 5 (from day 30). A relaxin blood test is reliable from around here and is the usual confirmation where ultrasound is not available. The abdomen may start to look fuller.

Week 6 (from day 40). Energy needs begin to climb. This is the point to move her onto a puppy or gestation diet, fed in smaller and more frequent meals as the growing uterus takes up space. See the feeding section below.

Week 7 (from day 45). Fetal skeletons have mineralized and are visible on X-ray. This is the only reliable way to count puppies, and it is worth doing — see why below.

Week 8 (from day 55). Set up the whelping box somewhere warm and quiet, and let her get used to it. Start taking her rectal temperature twice a day and writing it down.

Week 9 (days 61–63). Watch for the temperature drop. Rectal temperature falls below about 37.2 °C (99 °F) roughly 24 hours before whelping begins. Other signs: restlessness, nesting, refusing food, panting. Then puppies.

Get the litter count

An X-ray from day 45 tells you how many puppies to expect, and that one number changes how whelping is managed. Without it, there is no way to know whether a female dog who has stopped pushing after four puppies is finished or has a fifth stuck. With it, you know when she is done and when to call. It is the single most useful thing to do before the birth.

Feeding a pregnant dog

Roughly normal for the first five weeks — she is not “eating for six” yet, and gaining weight early in pregnancy is not helpful. From about day 40, requirements rise sharply. By the final week she may need 30 to 60% more than her usual maintenance, and during peak lactation two to four times maintenance, because milk production is enormously expensive.

The calorie calculator has “pregnant, last 21 days” and “nursing” as life-stage options and applies the standard multipliers. A puppy or growth diet is the usual choice from mid-pregnancy, because it is energy-dense and complete — she cannot eat enough of a light adult food to meet the demand.

When to call the vet during whelping

Have the emergency number written down and know the journey time before the due date. The decision to call is usually made at three in the morning by someone who has not slept, so decide the rules in advance. Call if:

• Strong contractions for 30 minutes with no puppy
• More than two hours between puppies when more are expected
• A puppy visible but stuck for more than ten minutes
• Green or black discharge before the first puppy appears
• She is exhausted, collapsed, or in obvious distress
• More than 72 days from mating with no sign of labor

Dystocia — difficult birth — is common in brachycephalic breeds and in toy breeds, and a planned caesarean is often safer than an emergency one. If you are breeding one of those, discuss it with the vet at confirmation, not at day 63.

After: the next heat

A female dog cycles again on her usual interval whether or not she was pregnant — roughly every six months for small and medium breeds, eight for large, and up to a year for some giant breeds — and she can conceive on that next cycle. If you do not intend to breed again, that is the window to plan around. The heat cycle calculator projects it.

A pregnancy calculator produces dates; it does not supervise a pregnancy. A first-time breeding in particular should have a vet involved from confirmation onwards.

Tools in this post

• Dog Pregnancy Calculator: Due Date and Timeline →

  Dog pregnancy calculator: enter the mating date for the due date (day 63), the normal 57 to 72 day range, and dated ultrasound, X-ray and whelping milestones.

• Dog Heat Cycle Calculator →

  Predict when your dog’s next heat is due from her cycle history, with the fertile window highlighted and the typical six-month interval explained.

• Dog Calorie Calculator →

  Calculate how many calories your dog needs per day from body weight, life stage and activity level, using the standard RER and MER veterinary formulas.

Sources

• Merck Veterinary Manual. Breeding Management of Bitches (estrous cycle and gestation).
• Johnston SD, Root Kustritz MV, Olson PNS. Canine and Feline Theriogenology. Philadelphia: WB Saunders; 2001. Standard reference text for canine gestation length and whelping. No free full text.