Dog Pregnancy Signs: Week-by-Week Guide

By Sarah Bennett, Certified Animal Nutritionist

Suspecting your dog might be pregnant can be exciting and a little nerve-wracking at the same time. Unlike humans, dogs don't have over-the-counter pregnancy tests, and some of the early signs are subtle enough to be easily missed — or mistaken for illness. Understanding what to look for, week by week, helps you support your dog through one of the most physically demanding experiences of her life.

Early Signs of Dog Pregnancy (Weeks 1–3)

During the first three weeks, hormonal changes begin but physical signs remain minimal. Many owners notice nothing at all. However, some dogs show early behavioral shifts: she may seem more affectionate than usual, seek extra cuddles, or conversely appear slightly withdrawn and quieter. These mood changes are driven by rising progesterone levels.

Around week 3, some dogs experience mild morning sickness — a canine equivalent that causes nausea, reduced appetite, or occasional vomiting. This typically resolves within a few days. You may also notice very slight nipple enlargement beginning around day 21, though this can be difficult to detect without a baseline comparison.

Week 4: First Detectable Changes

Week four is often when things become more apparent. The embryos are now implanting in the uterine wall, and the dog's body is ramping up to support their development. The most reliable early physical sign — nipple enlargement and a slight pinkish coloration — becomes more obvious now. The areolas may appear rounder and more prominent.

This is also the ideal window for veterinary confirmation. Ultrasound performed between day 25 and day 28 can detect heartbeats and confirm a viable pregnancy. Your vet can also give you an initial impression of litter size, though this becomes far more accurate later.

Appetite may begin to increase slightly as the body's energy demands grow, though some dogs still show reduced interest in food due to lingering nausea.

Weeks 5–6: Visible Physical Changes

By week five, the developing puppies are growing rapidly and the abdomen begins to visibly enlarge. A clear, odorless vaginal discharge may appear — this is normal mucus from the cervical plug and should not alarm you unless it becomes colored, bloody, or foul-smelling.

Your dog's appetite will likely increase noticeably. This is the time to consult your vet about adjusting her diet. Switching to a high-quality puppy food or a food specifically formulated for pregnant and lactating dogs is often recommended, as these provide the extra protein, fat, and calcium needed for fetal development.

Weight gain becomes measurable — expect roughly 25–30% of her pre-pregnancy body weight to be gained by the end of gestation in larger litters.

Weeks 7–8: Behavioral Shifts and Nesting

As the pregnancy progresses toward its final stretch, behavioral changes become very pronounced. Your dog may begin nesting behavior — scratching at blankets, rearranging bedding, seeking out quiet corners, and becoming protective of certain spaces. This instinctual behavior signals that whelping is approaching.

The abdomen is now large and round. You may be able to see and feel puppies moving under the skin, particularly when your dog is lying still. The mammary glands enlarge significantly in preparation for milk production, and you may notice the nipples beginning to express a small amount of colostrum (pre-milk) in the final days.

Week 9: Final Days Before Birth

In the last week of pregnancy, your dog will become increasingly uncomfortable. She may eat less as the puppies crowd her stomach, or she may have a final surge of appetite before labor begins. Restlessness, panting, and an inability to settle are all common.

A key milestone to monitor is her rectal temperature. A normal canine temperature is 38–39°C (100.4–102.2°F). When it drops below 37.8°C (100°F) and stays there for 12–24 hours, labor is typically 12–24 hours away. Take her temperature twice daily in the final week to track this shift.

Confirming Pregnancy: What Your Vet Can Do

Never rely solely on physical signs to confirm pregnancy. Several conditions — including phantom pregnancy (pseudocyesis) and pyometra (a serious uterine infection) — can mimic pregnancy signs. A veterinary visit is essential.

• Palpation: Experienced vets can feel distinct fluid-filled sacs around days 28–35, though this window is narrow.
• Ultrasound: The gold standard for early confirmation. Heartbeats are detectable from day 25. This also rules out reabsorbed embryos or complications.
• Relaxin hormone test: A blood test that detects relaxin, a hormone only produced during pregnancy. Reliable from about day 30.
• X-ray (radiograph): From day 45 onward, puppy skeletons are visible on X-ray. This is the most accurate way to count puppies and is especially important for breeds prone to dystocia (difficult birth).

Nutritional Needs During Pregnancy

A pregnant dog's caloric needs increase steadily, especially in the final trimester. During weeks 1–5, continue her regular high-quality adult diet. From week 5 onward, transition gradually to a puppy or performance formula with higher protein (at least 25%) and fat (at least 15%) content. By the final week of pregnancy, she may need 50% more calories than her baseline.

Avoid calcium supplementation during pregnancy — excess calcium can suppress the body's natural calcium-regulating mechanisms and contribute to eclampsia (milk fever) after birth. Always discuss supplementation with your vet.

Fresh water must be available at all times. Dehydration during pregnancy has serious consequences for both mother and puppies.