강아지 임신·수유 관련 호르몬 이상 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

My puppy is acting strange after birth — could it be a hormonal abnormality during pregnancy or lactation?

EndocrineQ&AMeongsiljang Veterinary Advisory Board

Abnormalities caused by hormonal changes during pregnancy and lactation in dogs are important signs that pet owners should be aware of. This content addresses frequently asked key questions.

Hormonal abnormalities related to pregnancy and lactation in dogs are important signs that pet owners must know

During pregnancy and lactation, a dog’s hormone levels shift dramatically, with significant changes in progesterone, prolactin, and oxytocin. Progesterone plays a vital role in maintaining pregnancy, and a deficiency (luteal insufficiency) can lead to miscarriage, resulting in the premature expulsion of the fetus. After birth, during the nursing period, the mother’s calcium and energy requirements increase substantially, which can lead to hypocalcemia (postpartum eclampsia) or hypoglycemia. These changes can affect not only the mother’s health but also the development of her nursing puppies, so it is crucial for owners to recognize these signs promptly. Familiarize yourself with the key symptoms and appropriate responses in advance.

What are the key causes of hormonal changes during pregnancy and lactation?

During pregnancy, progesterone levels remain elevated to help maintain a stable pregnancy. If progesterone is insufficient (a condition known as luteal insufficiency), it can lead to miscarriage, where the fetus is expelled before full term. After birth, during the nursing period, prolactin and oxytocin are released to stimulate the mammary glands and support milk production. Meanwhile, during pregnancy and the postpartum anestrus period, progesterone can increase growth hormone secretion, leading to insulin resistance and potentially diabetes. If you suspect hormonal changes, it is important to have your veterinarian monitor and manage hormone levels, including progesterone. Early detection helps prevent and manage complications.

A veterinarian gently examining the abdomen of a pregnant dog.

What are the main symptoms of hormonal abnormalities?

Hormonal imbalances or related conditions often present with nonspecific symptoms such as loss of appetite, lethargy, weakness, and weight changes. During lactation, a mother may suddenly become lethargic or exhibit neurological signs like tremors or seizures, which could indicate hypocalcemia (eclampsia) or hypoglycemia. Additionally, progesterone deficiency can lead to abnormal vulvar discharge or signs of premature labor. Early detection of these signs is crucial, so it’s helpful for pet owners to carefully monitor and record changes in appetite, activity levels, and weight.

A puppy that appears lethargic and has a roughened coat

Signs requiring immediate veterinary visit

If the mother dog exhibits severe vomiting, seizures, tremors, decreased consciousness, or collapses suddenly, she needs immediate veterinary attention. Seizures and profound weakness during lactation can indicate life-threatening emergencies such as hypocalcemia (eclampsia) or hypoglycemia. These conditions can jeopardize not only the mother’s health but also the survival of her nursing puppies. Prompt diagnosis and emergency treatment tailored to the underlying cause are critical for saving lives.

How are hormonal abnormalities diagnosed?

Veterinarians check hormone levels, including progesterone, through blood tests and evaluate for luteal insufficiency (low progesterone). Ultrasound examinations provide more detailed information than standard X-rays, helping to assess the condition of the fetus, uterus, and ovaries, and to detect any abnormalities early. From 20 to 21 days after mating, a relaxin test can confirm pregnancy and distinguish it from pseudopregnancy. Once pregnancy exceeds 67 days, more frequent check-ups are recommended, and all examinations and care should be conducted under veterinary guidance. Early diagnosis helps prevent complications.

A veterinarian drawing blood from a pregnant dog's leg.

What are the treatment methods for hormonal abnormalities?

Treatment varies depending on the specific condition diagnosed. If secondary hypothyroidism is confirmed, thyroid hormone medications such as levothyroxine may be used. In emergency situations like hypoglycemia or hypocalcemia, your veterinarian will provide targeted interventions, such as administering glucose or calcium supplements. Additionally, a nutritionally balanced diet and environmental management to reduce stress are essential components of care. Since your veterinarian will regularly monitor your pet’s weight and hormone levels to adjust the treatment plan, it is crucial to follow their guidance rather than self-medicating, as this is key to recovery.

A veterinarian administering a hormone injection to a pregnant dog

What are the management points at home?

- Regular weight checks: Record your pet’s weight once a week to catch any sudden changes. - Balanced nutrition: Choose food formulated specifically for pregnancy and lactation to ensure adequate nutrient intake. - Minimize stress: Provide a quiet environment where your pet can rest comfortably. - Monitor milk production: Check daily milk output and your puppies’ growth progress every day. - Regular veterinary consultations: Visit your vet every two weeks to monitor hormonal health. - Daily observation habits: Keep a careful record of appetite, activity levels, and bowel movements.

A pregnant dog resting comfortably in a quiet environment.

Comparison of stage-by-stage symptoms and countermeasures for hormonal abnormalities

Item	단계	주요 증상	대처법
경증	식욕 약간 감소, 가벼운 무기력	영양 보충, 휴식 제공, 경과 관찰	아니요
중등도	젖 분비 감소, 체중 감소, 식욕 부진	수의사 상담 및 호르몬·혈액 검사	예
심각	발작, 떨림, 의식 저하, 쓰러짐	즉시 병원 방문, 원인에 맞는 응급 처치(칼슘·포도당 등)	예

심각 단계는 저칼슘혈증(자간증)이나 저혈당처럼 생명을 위협할 수 있으므로 즉각적인 병원 방문이 필요해요.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently asked questions

When do hormonal imbalances occur during pregnancy?

Symptoms can appear from late pregnancy through the immediate postpartum period and into lactation. During this time, especially after giving birth and while nursing, the increased demand for calcium and energy can lead to hypocalcemia (eclampsia) or hypoglycemia.

Can hormonal imbalances be treated?

Yes, in many cases, the condition can be managed with medications or supportive treatments tailored to the underlying cause. Diagnosis and treatment should always be carried out under the guidance of a veterinarian, and early detection is key.

Should I change my dog’s food during pregnancy?

Yes, it's recommended to switch to a diet specifically formulated for pregnant and nursing pets. Since proper nutritional balance is crucial, please follow your veterinarian's advice.

Can hormonal imbalances affect puppies?

Yes, a deficiency in progesterone in the mother can lead to miscarriage, and the mother's nutritional and health status can affect the development and survival of the puppies. Puppies that are significantly underweight compared to the average have lower survival rates, so early management is important.

My nursing puppy has suddenly become lethargic. What should I do?

You should take your pet to the vet immediately. Sudden lethargy during lactation can be a sign of serious conditions such as hypoglycemia or hypocalcemia (eclampsia).

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References

[1] Serrano et al. (1964) Nutrient Requirements of Dogs and Cats. National Academies Press.

[2] Applied Veterinary Clinical Nutrition, 2nd Ed. (2010). Blackwell Publishing.

[3] Shawcross, G. (2011). 100 Top Consultations in Small Animal General Practice. Blackwell Publishing.