PREGNANCY - FROM SINGLE CELL TO A PUPPY

A dog's pregnancy lasts about 63 days. Depending on the time difference between ovulation and fertilization, gestation periods between 60 and 66 days are completely normal. Additionally, large litters are often born a little earlier, while smaller litters tend to take a bit more time.
While nothing is visible on the outside, fascinating things are happening inside females.

​Day 1
Mating and Sperm Journey
On the first day of mating, the male dog may release approximately 500 million sperm. However, these sperm are not immediately capable of fertilizing an egg; they must first undergo a maturation process known as capacitation, which takes about 6 to 10 hours.
Once released, the sperm travel through the cervix and into the fallopian tubes. The fastest swimmers can reach the tubes in as little as 15 to 45 minutes, while the rest may take up to three hours. At this stage, the female may either be approaching ovulation or may have already released eggs, setting the stage for fertilization.

Day 2
Sperm Seek the Egg
​After completing the maturation process, the "cleaned" sperm continue their journey through the female's reproductive tract in search of an egg to fertilize. If ovulation has already occurred, fertilization may take place soon. If not, the sperm can survive inside the female’s body for several days, waiting for the eggs to be released.

Day 3
Opportunity for a Second Mating
​After 48 hours, a second mating can be performed to increase the chances of successful fertilization. Since sperm can survive in the female’s reproductive tract for several days, repeated matings during the fertile window help ensure that viable sperm are present when ovulation occurs.

​Day 4
​Fertilization and Early Pregnancy Care
​By now, fertilization occurs as the sperm meet the released eggs in the fallopian tubes. This marks the beginning of pregnancy. Enzymes help loosen the egg’s outer membrane, allowing the sperm to penetrate. For this process, the enzymatic activity of at least 100,000 sperm is required per egg.
However, only one sperm successfully penetrates the membrane and fertilizes the egg.During the first third of gestation, no special care is required for the female. There is no need to change her diet or feeding amount at this stage. She can engage in as much physical activity as she desires. However, in hot weather, excessive exercise should be avoided to prevent overheating and dehydration.

Days 5–11
Journey to the Uterus
​The fertilized eggs (zygotes) begin their journey from the fallopian tubes to the uterine horns. This process takes several days as the embryos slowly travel and prepare for implantation. At this stage, the female’s behavior and physical condition remain unchanged, and no special care adjustments are needed.

​Day 12 & 13
​Embryos Begin Nesting
​The early embryos, now about 0.6 mm in size, shed their protective outer layers and begin floating freely in the uterine fluid. During this stage, they move around, searching for the ideal spot in the uterus where they will eventually implant and continue developing.
​The surrounding fluid is a food source for the embryo before nesting.

Between days 12 and 15, the uterine lining forms local swellings (ampullae), marking the beginning of the formation of the amniotic sacs. Each future puppy now finds its place within the uterine horns.

​Day 14
Early Fetal Development
On day 14 of pregnancy, the embryo starts migrating within the womb. The embryos spread out and settle in different areas of the uterine corners, where they will soon begin attaching to the uterine wall for nourishment and further growth.
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​Day 15
Critical Development Phase
During the next two weeks, the vital organs of the embryo begin to develop. This period is crucial, and it's important to avoid any interventions that could affect the mother’s body, as they can also impact the embryo. Avoid using flea or deworming treatments during this time. The mother is sensitive to any changes, so it’s essential to maintain her regular routine, including walking times, feeding habits, and resting places. Any changes or interventions should be carefully noted in a calendar. This is a sensitive time for organ development, and until day 35, the uterus can fully absorb the embryo or fetuses.

Day 16
Physical Changes in the Mother 
​On day 16, the female's body starts showing physical changes as the pregnancy progresses. Her nipples become pinker and enlarge, and the coat around her belly and nipples may start thinning. At this stage, the embryo is around 1mm in size, still developing in the early stages.

Day 17
Embryo Development 
On day 17, the embryos begin nesting into the uterine wall. During this time, the nervous system starts to develop first, followed by the formation of the head and body structures of the embryos. This marks an important phase in their growth.


Day 18
​Placenta and Nervous System Development 
On day 18, the placenta begins to develop, providing the embryo with nutrients and oxygen. The nervous system continues its development, laying the foundation for the embryo's future growth. At this stage, the embryo is approximately 2mm in size.

Day 19
​Internal Organ Development
On day 19, the embryos begin the development of their internal organs. This marks a critical stage in the growth process, as the foundational structures of essential organs start to form.

​​Day 20
Placenta Development and Pregnancy Confirmation 
​On day 20, the development of the placenta continues, and marginal bleeding may occur around it. The blood pigment hemoglobin changes to green hematochlorin, which can discolor the amniotic fluid during birth. At this stage, it's possible to confirm the pregnancy through abdominal palpation or ultrasound examination, about 20 days after mating. The embryo is approximately 4mm in size.

​Day 21
Placenta and Heart Development 
​On day 21, the placenta is fully formed, and the foundation for the development of the heart is laid. At this point, pregnancy can be confirmed, and while the embryo may not yet be visible on ultrasound, the amniotic fluid-filled afterbirths can be seen. The embryo is around 5mm in size.

Day 22
Ultrasound Diagnosis and Pregnancy Symptoms 
​On day 22, the ideal period for confirming pregnancy through ultrasound begins. During this time, the female may experience morning sickness and a loss of appetite due to hormonal changes and tension in the womb. She may appear apathetic, lack mood, and in some cases, vomiting may occur. To help, divide her meals into smaller doses and offer flavored food. A harmless vaginal discharge, clear or resembling egg white, may also appear.

Day 23
Development of Facial Features and Organs 
​On day 23, the embryos begin developing key features such as eyes, ears, nose, jaw, and liver. At this stage, the embryo measures approximately 10mm in size. This is also an ideal time for confirming pregnancy via ultrasound.

Tail bud embryo with optic vesicles, branchial arches, and heart bulge.

​​Day 24
Organ Development and Fetal Growth
On day 24, the major organs of the embryo continue to develop rapidly, but actual fetal growth slows down as these structures mature. This is still an ideal period for ultrasound diagnosis to confirm pregnancy.

​Day 25
Heartbeat and Continued Organ Development 
​On day 25, the ideal period for ultrasound diagnosis of pregnancy continues. During an ultrasound, the heartbeat of the fetuses can now be detected. The embryos begin developing teeth, the spine, and limbs. At this stage, the embryos are approximately 14mm in size.

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​Day 26
Pregnancy Confirmation and Embryo Growth 
​On day 26, it's still the ideal period for ultrasound diagnosis of pregnancy. An experienced person can also use palpation to diagnose pregnancy, as the embryos have grown to about the size of a walnut, making it easier to count them. This is a good time to start limiting strenuous movements for the female. The development of teeth, the back, and the limbs of the fetuses continues.

Day 27
​Ultrasound Diagnosis 
On day 27, it remains the ideal period for ultrasound diagnosis of pregnancy. This is an important time to confirm the pregnancy and observe the development of the embryos.

​Day 28
Development of the Jaw and Skull 
On day 28, the ideal period for ultrasound diagnosis of pregnancy continues. During this time, ossification (the process of bone formation) of the jaw and skull begins. The shape of the fetus changes from an ovoid shape to a more spherical form. At this stage, the fetus is about 17mm in size.
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Day 29
Miniature Dog-like Appearance and Feeding Adjustments 
On day 29, the fetus now resembles a miniature dog, with more defined features. It's time to start gradually increasing the female's food ration to support her pregnancy. However, be careful not to overfeed, as excessive weight gain should be avoided to prevent any complications.

Day 30
​Complete Ossification of the Jaw and Skull 
​On day 30, the ossification of the jaw and skull is complete. The embryo is now around 2cm in size, with more fully formed features and bone structure.

​Day 31
Growth of Sensory Hairs 
On day 31, sensory hairs begin to grow on the chin, eyebrows, and nose of the embryo. These sensory hairs, also known as vibrissae, are important for the embryo's sensory development.

Day 32
Mid-Gestation Growth 
On day 32, the embryo reaches approximately 20% of its size at birth. This marks a significant stage in the development as the fetus continues to grow and mature.

​Day 33
Development of Limbs and Organs 
On day 33, the fetus experiences growth in its fingers, and ossification (bone development) continues in the nose, ribs, and leg bones. The development of all major organs is now complete. At this stage, the fetus is about 27mm in size.
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Day 34
​Behavioral and Physical Changes in the Female 
​On day 34, the female begins to show behavioral changes, becoming quieter and more sensitive. Her abdomen and external genitalia start to slightly increase as the pregnancy progresses. By day 35, the fetus may still be absorbed, and later, during birth, the fetus may be delivered as a black fetus.

​Day 35
Completion of Organ Development and Increased Appetite 
By day 35, all major organs of the fetus are fully developed, and the fetus is about 35mm in size. The female's appetite increases, and it's advisable to start feeding her food specifically formulated for pregnant females. Increase the amount by 10% and divide her ration into 2 to 3 meals a day.

Day 36
Rapid Growth Begins 
​On day 36, the slow growth phase of the fetus ends, and rapid growth begins. This growth phase starts with the development of the reproductive system, continued skeletal ossification, and the formation of the scapula.

Day 37
Fastest Growth Stage 
Day 37 marks the beginning of the fastest growth phase for the fetus.

Day 38
Physical Changes in the Female 
On day 38, the female begins to slowly gain weight as the uterus expands. You may notice an increase in volume around the area of the last ribs and slight enlargement of the mammary glands.
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Day 39
​Accelerated Fetal Growth 
​By day 39, fetal growth accelerates, and skeletal ossification continues.

Day 40
Development of Hair and Organ Formation 
On day 40, the fetuses have established almost all internal organs. The first signs of hair start appearing on the head, and the eyes are closed. The fetuses are about 65mm in size.

Day 41
30% of Birth Size and Bone Development 
By day 41, the fetus is about 30% of its total size at birth. Ossification continues in the spine and fingers.

Day 42-43
Continued Ossification and Growth 
During days 42 and 43, ossification of the spine and fingers continues, and rapid growth of the fetus persists.

​Day 44
Uterine Expansion and Feeding Adjustments 
On day 44, the female’s uterus occupies about two-thirds of the abdominal cavity. Hair loss and thinning hair may appear on the mammary glands. It becomes easier to feel the puppies, but counting them may be harder. It's recommended to feed her 3 to 5 times a day in smaller doses, increasing the total amount by 15-20%. Avoid steep and strenuous movements or jumping.

Day 45
Ossification of Pelvis and Coat Development 
By day 45, ossification of the pelvis continues, and the fetuses begin to grow their coats.
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Day 46
​X-ray to Count Fetuses 
​On day 46, ossification of the pelvis continues, and the fetuses grow their coats. X-rays can now reveal the skeletons of the fetuses, allowing for an accurate count by observing the skulls and spines.

Day 47
Coat Growth Continues 
On day 47, ossification of the pelvis continues, and the fetuses' coats continue to grow.

Day 48
Visible Size Increase and Appetite Changes 
By day 48, the female starts to become visibly larger. At this stage, she may lose her appetite as the fetuses push against her internal organs, especially the digestive tract.

Day 49
75% of Birth Size and Preparing for Birth 
On day 49, the fetuses reach 75% of their size at birth. It's time to accustom the female to the box in which she will give birth, helping her adjust to the new environment.

Day 50
Organ Development and Increased Movement 
By day 50, the fetuses’ organs are well developed, and their movements (swarming) become noticeable. The female may lose her appetite (though this is not always the case), so it’s important to feed her more often in small doses. The total daily dose should be increased by 25-50%.

Day 51
Searching for a Birth Location 
On day 51, the female starts to relax and look for a suitable place to give birth.

Day 52
Milk Production Begins 
At this stage, some females may experience spontaneous milk release from the teats. The female often rests and prepares for labor.

Day 53
Resting and Preparing for Birth 
By day 53, the female is still resting and preparing for the birth.
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Day 54
Final Organ Development 
On day 54, the female continues to rest, and the last internal organ, the lungs, complete their development.

Day 55
Coat and Claw Development 
By day 55, the fetus is fully covered in a coat, though the coat on the feet is still less visible. The claws are fully developed, and skin pigmentation begins. The fetus is around 145mm in size, and the female is still resting and preparing for birth.

Day 56
​Tooth Calcification 
​On day 56, the calcification of teeth begins. The female continues to rest and prepare for labor.

Day 57
Pronounced Fetal Movement and Swollen Mammary Glands 
​On day 57, the movements of the fetuses become more pronounced, and the female’s mammary glands are significantly swollen. The female is still resting and preparing for the birth.

​Day 58
Lungs Developed and Fetus Viable 
By day 58, the fetuses' lungs are fully developed, making them viable. The female continues to rest and prepare for labor.

Day 59
Physical Changes and Preparation for Birth 
​On day 59, the female’s belly becomes loose, the uterus starts to decrease in size, and her body is preparing for childbirth. It's time to ensure everything is ready for the birth. Begin measuring and recording the female’s rectal body temperature twice daily, in the morning and evening, to track any temperature changes as birth approaches.
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​Day 60-65
​Expected Birth Window 
​Days 60 to 65 mark the expected window for birth, although the birth can occur between day 59 and day 67. Shortly before birth (12-24 hours), the female may stop eating normally, and her body temperature will decrease from 38-39°C to 36.5-37.5°C (a drop of 1-2°C). Hormonal changes trigger uterine contractions, which gradually lead to abdominal contractions and the expulsion of the fetus. The delivery process may vary for each female, so it’s important to monitor her closely during this time.

​Puppy development from birth to 12-weeks
​Puppies are born blind, deaf and toothless, and are unable to regulate their own body temperature for at least the first three weeks. A newborn pup depends on its mother and littermates for warmth and may also require additional environmental heat supplementation when necessary.

1 day old puppy

Birth to 1 Week

• Blind, Deaf, and Toothless: Puppies are born with their eyes and ears closed, and they do not have teeth. They rely on their mother and littermates for warmth and comfort.
• Body Temperature Regulation: Newborn puppies cannot regulate their body temperature for the first three weeks, so they depend on external warmth, either from their mother or environmental heat sources if necessary.
• Feeding: They nurse from the mother frequently for sustenance, and this early nutrition is vital for growth and development.
• Movement: While they are not very mobile at this stage, they can crawl toward their mother’s scent or warmth.

1st week

1st week

2 to 3 Weeks

• Eyes and Ears Open: By the second week, puppies’ eyes begin to open, although their vision is still blurry. Their ears open around this time, but they can’t hear well yet.
• Teeth Begin to Emerge: Their baby teeth begin to grow, and they may start to show some early exploration behaviors, like gentle biting.
• Crawling and Early Play: Puppies begin to move more, slowly crawling and eventually beginning to take their first wobbly steps.
• Socialization: They start interacting more with their littermates and mother, playing and beginning the early stages of social learning.

3 weeks

​4 to 6 Weeks

• More Mobility and Playfulness: Puppies are now much more mobile and start exploring their environment more actively.
• Tooth Development: Their teeth continue to grow, and they may begin to nibble on solid foods if introduced by their mother.
• Increased Senses: Their sight and hearing continue to develop, allowing them to interact with their surroundings more effectively.
• Social Learning: They continue to develop critical social skills by interacting with their littermates and mother, including bite inhibition and appropriate play behavior.

4 weeks

5 weeks

6 weeks

7 weeks

​7 to 9 Weeks

• Weaning Begins: By now, puppies are usually weaned off their mother’s milk and start eating solid food. Their baby teeth are fully formed.
• Senses Fully Developed: Their vision and hearing are now fully functional, and they become more aware of their environment.
• More Play and Exploration: They are very active, playful, and curious, engaging in more interactive play with both their littermates and humans.
• Learning Socialization Skills: The early stages of socialization are crucial during this time, and they begin to learn about their place in the world, including appropriate interactions with humans and other animals.

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8 weeks

9 weeks

After 9 weeks it is the best that puppies move to their new homes :)

10 to 12 Weeks

• Increased Independence: Puppies continue to grow rapidly, and their play becomes more coordinated and complex. They start to show signs of increased independence and curiosity about the world.
• Socialization and Bonding: This period is critical for establishing strong bonds with humans. Early training, socialization with new experiences, people, and environments, and exposure to other animals help them grow into well-adjusted adult dogs.
• Development of Strength and Coordination: By the end of week 12, puppies are much more agile and confident in their movements, though they still need to be guided and trained.

During the first 12 weeks, it’s important to provide the right balance of nutrition, socialization, and training to support the puppy’s development into a healthy, well-adjusted adult dog.
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photos: National Geographic