How Long After Heat Does A Dog Show Pregnancy?

The gestation period for dogs is an important topic for dog owners and breeders to understand. Knowing how long dogs are pregnant and what signs to look for can help owners prepare for whelping and raising a litter. This article will provide an overview of the canine gestation timeline from heat cycle to birth. It will cover the breeding and conception process, early pregnancy signs, ultrasounds, behaviors, preparing for delivery, and more. By the end, readers will have a comprehensive understanding of what to expect during the 63 days from the start of a dog’s pregnancy to new puppies.

The Heat Cycle

The heat cycle, also known as the estrous cycle, is the period when a female dog can become pregnant. The heat cycle occurs every 6-8 months and lasts approximately 18-21 days (WebMD). There are four stages of the canine heat cycle:

Proestrus – This stage lasts approximately 7-10 days. The uterine lining begins to grow and follicles in the ovaries start to mature. At this stage, dogs will attract males but will not allow breeding. Vaginal bleeding may occur.

Estrus – The estrus stage lasts approximately 5-10 days. Hormone levels peak and the female is receptive to the male for breeding. The vulva swells and bleeds. This is the stage where conception is most likely to occur if the dog mates.

Diestrus – Diestrus lasts approximately 2-3 months and is the period after breeding. Hormone levels decrease and the female will no longer allow breeding. The uterine lining continues to proliferate in preparation for pregnancy.

Anestrus – Anestrus refers to the resting period when the female dog is not in heat. This stage lasts anywhere from 3-9 months (VCA Hospitals). Hormone levels are low and the female will not go into heat during this time.

Breeding and Conception

The optimal time for breeding a female dog during her heat cycle is generally between days 10-14 from the start of bleeding. This window corresponds to when she is most fertile and likely to conceive. According to VCA Animal Hospitals, “For most females, the best time for breeding is between the tenth and fourteenth day of estrus” (Source). This is when ovulation typically occurs.

Conception happens when a male dog’s sperm fertilizes the female’s eggs during breeding. This occurs in the oviducts shortly after ovulation. If the eggs are fertilized, they will move into the uterus where the embryos will implant into the uterine lining approximately 18-20 days after ovulation (Source). Therefore, conception itself happens within a day or so of breeding, but it takes up to 3 weeks after ovulation/breeding for the embryos to implant and pregnancy to be established.

Early Signs of Pregnancy

In the first few weeks of pregnancy, there are some early signs that indicate a dog is expecting puppies. These early symptoms often mimic signs that a dog is coming into heat but are distinctly different.

One of the earliest signs is a change in the dog’s appetite. Pregnant dogs may start eating more frequently and show an increase in appetite as early as 2 weeks into the pregnancy. This is due to the nutrients required for the developing puppies.

Other physical signs in the first few weeks include swollen or enlarging nipples, a firm or swollen abdomen, and possible spotting. The dog’s nipples may turn slightly red and enlarged around 3-4 weeks into the pregnancy.

Behavioral changes are also common in the early stages. The pregnant dog may seek more affection and seem more tired. Some dogs exhibit signs of morning sickness with vomiting or nausea. Irritability and restlessness are also potential symptoms of early dog pregnancy.

An experienced breeder or veterinarian can detect pregnancy as early as 3-4 weeks in by gently palpating the abdomen. But most dogs don’t show obvious physical signs until closer to 5-6 weeks. The early weeks are critical for providing proper care and nutrition to support a healthy pregnancy.

Morning Sickness

Like humans, some dogs can experience “morning sickness” in the early stages of pregnancy, usually around 3-4 weeks after conception. This is caused by hormonal changes and may cause nausea, vomiting, and/or decreased appetite. According to the Starvet Clinic, morning sickness only lasts a few days in most dogs. Signs to look for include:

  • Vomiting
  • Loss of appetite
  • Lethargy

WebMD also notes that morning sickness affects some dogs for just a few days during the 3rd or 4th week of pregnancy. However, dramatic vomiting or signs of illness beyond a few days may indicate a more serious health issue, so it’s a good idea to contact your veterinarian.

Visible Physical Changes

Around day 40 of pregnancy, the pregnant dog’s belly will begin to noticeably expand as the puppies grow and the uterus enlarges. According to Purina, the belly doesn’t just get larger, but the dog’s waistline also fills out. Some swelling in the nipples may also be noticeable around this time.

By day 45, the pregnant dog’s belly will be clearly distended. As her due date approaches, she may appear rectangular when viewed from behind as the puppies take up more room in her abdomen. The fur over her pregnant belly may become thinner as the skin stretches to accommodate the growing puppies.

According to AskVet, other physical changes like lethargy, increased appetite, and enlarged/darkened nipples become more pronounced in the second half of pregnancy as well. The enlarging uterus puts pressure on the diaphragm, making breathing slightly more difficult, which contributes to lethargy. As delivery approaches, the pregnant dog may start nesting behaviors like shredding bedding and searching for a quiet space.

Ultrasounds and X-Rays

Ultrasound is the most accurate way to confirm and monitor a dog’s pregnancy after 3-4 weeks. An ultrasound uses high frequency sound waves to create images of the puppies and placentas. According to VCA Hospitals, ultrasound is the “gold standard” for detecting pregnancy and assessing fetuses as early as 3-4 weeks after mating.

Ultrasounds allow veterinarians to count the number of puppies, estimate due dates, check for heartbeats, and measure growth. They can be done multiple times throughout pregnancy for ongoing monitoring. Limitations include inability to accurately count large litters and potential for false negatives if done too early. X-rays can supplement ultrasounds later in pregnancy to count skeletons and estimate size.

East Central Veterinary Hospital states 30 days after breeding is a great time for an ultrasound to confirm pregnancy. While not as accurate for counting puppies, it can detect heartbeats and measure fetal size. Most veterinarians recommend an ultrasound around 4 weeks, with follow up scans at 6-8 weeks and again closer to delivery.


Behaviors and Care

A pregnant dog’s behavior and care needs will change as her pregnancy progresses. According to the AKC, during the first few weeks of pregnancy, there may be few outward signs that a dog is expecting puppies [1]. However, as the pregnancy advances, hormone fluctuations and physical changes will lead to behavioral shifts.

Around week 4, a pregnant dog may act more tired and want to rest more often. Her appetite will also increase to support the growing puppies. It’s important to feed high-quality puppy food formulated for gestation and lactation [2].

In the middle weeks of pregnancy, dogs often exhibit nesting behaviors, searching for secluded and comfortable places to give birth. More affection, attention-seeking, and clinginess are also common. Providing a whelping box, toys, and frequent positive interactions can help meet a pregnant dog’s needs.

In the final 3 weeks, lethargy, restlessness, panting and anxiety may increase as hormones surge and the birthing time draws near. Limiting stress and exercise while providing reassurance through petting and gentle massage is important. Monitoring for potential complications and preparing for delivery is crucial during this time.

With the right diet, space, socialization and veterinary care, dog owners can help promote healthy pregnancies and prepare for the arrival of puppies.

Preparing for Delivery

As your dog’s due date approaches, you’ll want to prepare for the big event! Here are some signs that labor is imminent and tips for getting ready for whelping:

In the final week of pregnancy, your dog’s body temperature will drop below 100°F, signaling that labor is likely to start within 24 hours. You may also notice changes in appetite, nesting behavior, panting, and enlarged mammary glands. Prepare a whelping box in a quiet area with plenty of newspaper, towels, and blankets. Make sure you have clean supplies like dental floss and scissors on hand to tie off umbilical cords. Your vet may recommend calcium supplements and whelping assistance if needed.

When your dog goes into active labor, encourage her to lie down in the whelping box. Puppies are usually born every 30-60 minutes, so offer praise and reassurance during contractions and breaks between pups. Use towels to gently clean off newborns and stimulate breathing if needed. Let the mother chew through umbilical cords naturally or tie them off yourself several inches from the puppy’s belly. Monitor for any birthing complications and have your vet’s emergency contact handy just in case.

With preparation and support, you can help your dog have a safe, smooth whelping experience. Reach out to your vet with any questions as your dog’s due date nears.


In summary, the timeline for detecting signs of pregnancy in dogs after a heat cycle mating can vary. Some dogs may start exhibiting behavioral changes or physical symptoms like morning sickness as early as 2-4 weeks after conception. At around 4 weeks, an ultrasound or x-ray can often confirm pregnancy. By 5-6 weeks, many dogs will start to show visible weight gain, enlargement of mammary glands, and distension of the abdomen. Finally, around day 63 from mating, physical and behavioral changes will peak as the dog nears labor and delivery.

It’s important to monitor your dog closely during the pregnancy timeline and seek veterinary advice. An examination and testing can help confirm the pregnancy, estimate delivery dates, and detect any potential complications or health issues. With proper prenatal care and preparation, you can ensure your pregnant dog stays happy and healthy throughout the process of bringing a new litter into the world.

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