Visual Signs of Dog Labor: Stages of Whelping, Temperature Drop, Normal vs. Emergency Discharge

Visual Signs of Dog Labor: Stages of Whelping, Temperature Drop, Normal vs. Emergency Discharge

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Reviewed by a Doctor of Veterinary Medicine (DVM)
Veterinary Reproductive Medicine & Theriogenology
Whelping – the process of parturition in dogs – is a natural process that most dogs complete without intervention. However, recognizing the normal stages of labor, their expected duration, and the signs that indicate a complication requiring emergency veterinary attention is essential knowledge for any owner managing a pregnant dog through delivery. Dystocia (difficult birth) occurs in approximately 5% of all canine deliveries and significantly more frequently in certain breeds, including brachycephalic breeds (English Bulldogs, French Bulldogs, Boston Terriers), breeds with large heads relative to the maternal pelvis, and breeds selected for very large puppy size relative to litter size. Understanding what normal labor looks like, how long each stage should last, and which specific deviations from normal are emergencies requiring immediate veterinary intervention is the knowledge that protects both the mother and the puppies.

Key Takeaways

  • Canine labor has three distinct stages. Stage 1 (preparatory stage, 6-24 hours) is characterized by uterine contractions that are not yet visible externally, combined with behavioral signs: restlessness, nesting, panting, shivering, vomiting in some females, and refusal to eat. Rectal temperature drops from a normal 38.3-39.2°C (101-102.5°F) to below 37.8°C (100°F) approximately 12-24 hours before active labor begins – this temperature drop is one of the most reliable pre-whelping signs. Stage 2 (active delivery of puppies) involves visible abdominal straining and delivery of individual puppies, with each pup typically delivered within 30-60 minutes of active straining. Stage 3 (expulsion of placentas) is interleaved with Stage 2 – each placenta is typically passed within 5-15 minutes after each puppy, though placentas may occasionally be retained temporarily.
  • Body temperature monitoring is the most reliable method for predicting imminent whelping. As progesterone levels fall in the 24-48 hours before parturition, rectal temperature drops characteristically to below 37.8°C (100°F), most typically to 37.2-37.5°C (99-99.5°F). This drop is transient – temperature returns to normal within 12-24 hours as labor begins – but its occurrence signals that active labor will begin within 12-24 hours. Owners who monitor rectal temperature twice daily starting at approximately day 57 of gestation (counting from the LH surge) will catch this drop and have advance warning to prepare. A single temperature reading of 37.8°C (100°F) that was not preceded by a lower reading may be a false start; waiting for a confirmed drop to below 37.5°C (99.5°F) before calling the veterinary clinic to alert them is appropriate.
  • Each puppy should be delivered within 30-60 minutes of the onset of active, visible straining. Active straining is defined as visible abdominal contractions – the abdomen visibly tightening and the dog bearing down – occurring repeatedly. If strong, active straining has been occurring for more than 20-30 minutes without delivery of a puppy, or if more than 4 hours have passed since the last puppy was delivered and the dog is still showing signs that more puppies remain (persistent restlessness, licking at vulva without delivery, abdominal palpation suggesting retained fetuses), emergency veterinary evaluation is required. These are the primary time-based criteria for obstetric emergency in dogs.
  • Green or black vaginal discharge before any puppy has been delivered is an emergency sign. The greenish-black discharge (uteroverdin) comes from the marginal hematoma of the placenta and is normal – but only during active delivery when it indicates placental separation. If green or black discharge appears before the first puppy is born, it suggests placental separation has begun without delivery, which is an obstetric emergency because the affected puppy or puppies may be hypoxic. Clear, translucent-white, or pale straw-colored fluid (from the amniotic sac or chorioallantois) is normal before and during delivery. Bright red blood, purulent discharge, or black necrotic discharge at any point during or after whelping warrants emergency veterinary evaluation.
  • The total number of puppies expected should be confirmed by abdominal radiograph at day 55+ of gestation, before whelping begins. Radiographs allow counting of fetal skulls and spines (the most visible skeletal structures), providing an expected number. Knowing this number is clinically critical because it allows the owner and veterinarian to know when the litter is complete – if the expected number has not been born and labor has apparently ceased, retained fetuses requiring intervention can be identified promptly. Without a pre-whelping radiograph count, a retained fetus may not be recognized for hours or days, during which time metritis (uterine infection), fetal decomposition, and systemic illness develop. Pre-whelping radiograph is considered standard preparation by veterinary theriogenologists.

The Three Stages of Canine Labor

Stage Duration What You See What Is Happening
Stage 1 – Preparatory 6-24 hours (up to 36 hours in first-time mothers) Restlessness; nesting; panting; shivering; vomiting; refusal to eat; seeking seclusion; temperature drop Uterine contractions beginning (not visible externally); cervix dilating; progesterone falling; oxytocin rising
Stage 2 – Active delivery Variable: 1-24+ hours total depending on litter size; each puppy within 30-60 minutes of active straining Visible abdominal straining; bearing down; clear or blood-tinged fluid; delivery of puppies in amniotic sac or not; green-black discharge between/during deliveries (normal) Uterine contractions propelling fetuses through birth canal; cervix fully dilated; each puppy delivered individually
Stage 3 – Placental delivery 5-15 minutes per placenta; interleaved with Stage 2 Passage of dark greenish-black fleshy placenta; dam may eat placentas (natural behavior, acceptable in limited quantity) Uterine contractions expelling placenta after each puppy; uterine involution beginning

Pre-Labor Signs in the 24-48 Hours Before Whelping

Temperature drop – the most reliable indicator

Rectal temperature in pregnant bitches is normally 38.3-39.2°C (101-102.5°F). As progesterone drops in the final 24-48 hours before parturition, rectal temperature characteristically falls to below 37.8°C (100°F), most commonly to 37.2-37.5°C (99-99.5°F). This drop is a direct consequence of progesterone’s thermogenic effect being removed as the corpus luteum regresses.

Protocol for monitoring: Beginning at day 57 post-ovulation, take rectal temperature twice daily (morning and evening) at consistent times. Record each reading. When a reading below 37.8°C (100°F) is recorded and confirmed on the next measurement, active labor can be expected within 12-24 hours. Temperature returns to normal range as active labor begins.

Behavioral and physical pre-labor signs

  • Nesting behavior: Scratching, digging, circling, and rearranging bedding to create a nest in the whelping box or a chosen secluded location
  • Restlessness and inability to settle: Getting up and lying down repeatedly, pacing
  • Panting: Often the first behavioral sign; may persist throughout Stage 1
  • Shivering or trembling: Not indicative of cold but of hormonal changes and discomfort from uterine contractions
  • Vomiting or retching: Occurs in some females during late Stage 1; not a sign of illness in this context
  • Anorexia: Refusal of food in the 12-24 hours before whelping is normal
  • Mammary gland engorgement: Milk production increases; glands become visibly engorged
  • Vulvar relaxation and discharge: The vulva softens further; clear mucoid discharge increases

Signs of Normal Active Labor

  • Visible abdominal contractions (the abdomen tightening rhythmically)
  • Bearing down (straining posture – similar to defecation effort)
  • Clear, pale straw-colored, or slightly blood-tinged fluid (rupture of amniotic sac)
  • Dark greenish-black discharge (uteroverdin from placental separation – normal during active delivery)
  • Delivery of puppy in or out of its amniotic sac
  • Dam breaking the amniotic sac and licking the puppy to stimulate breathing (instinctive maternal behavior)
  • Passage of dark fleshy placenta within 5-15 minutes of each puppy
  • Rest periods between puppies (up to 4 hours is within normal range if the dam is calm and not actively straining)

Emergency Signs Requiring Immediate Veterinary Attention

Call your veterinarian immediately if you observe any of the following
These signs indicate dystocia (difficult birth) or other obstetric emergency requiring prompt intervention:

  • Strong, active, visible straining for more than 20-30 minutes without delivery of a puppy
  • More than 4 hours between puppies with no delivery, if you know or suspect more puppies remain
  • Green or black discharge appearing before the delivery of any puppy
  • A puppy or fetal membranes visibly protruding from the vulva for more than 5-10 minutes without progression
  • Bright red blood loss greater than a small amount at any point during labor
  • Pale or white gums in the dam (indicates shock, blood loss, or cardiovascular compromise)
  • Collapse, extreme weakness, or loss of consciousness in the dam
  • Foul-smelling discharge (suggests uterine infection, retained decomposing fetus)
  • Total labor duration exceeding 24 hours without completion
  • Expected number of puppies (from pre-whelping radiograph) not delivered and labor appears to have stopped

Frequently Asked Questions

What are the first signs of labor in dogs?

The first signs typically appear 12-24 hours before active delivery and include: rectal temperature dropping below 37.8°C (100°F), restlessness and inability to settle, nesting behavior (scratching and rearranging bedding), panting, shivering, and often refusal to eat. Some females vomit during late Stage 1. These behavioral signs indicate Stage 1 labor, during which uterine contractions are occurring but are not yet visible externally and the cervix is dilating. Active, visible straining marks the transition to Stage 2 and the imminent delivery of puppies.

How long does dog labor last?

Stage 1 (preparatory) lasts 6-24 hours, sometimes up to 36 hours in first-time mothers. Stage 2 (active delivery) varies from 1 hour for a single-puppy litter to 24 or more hours for a large litter – total whelping time is primarily determined by litter size and how quickly individual puppies are delivered. Each puppy should be delivered within 30-60 minutes of the onset of active straining for that puppy. Rest periods between puppies of up to 4 hours are within normal range when the dam is calm and not actively straining.

What color should the discharge be during dog labor?

Normal discharges during labor: (1) Clear, pale straw-colored, or slightly blood-tinged fluid from rupture of fetal membranes – normal. (2) Dark green or black discharge (uteroverdin from placental hematoma) – normal during active delivery after the first puppy begins to arrive. (3) Dark fleshy greenish-black placenta passed after each puppy – normal. Abnormal: bright red blood in large amounts, purulent (pus-like) discharge, foul-smelling discharge, or green/black discharge before any puppy has been delivered. The last one particularly is an emergency.

What do I do if a puppy is born in the amniotic sac?

If the dam does not immediately break the sac and lick the puppy – which she usually will within 30-60 seconds – you must intervene. Tear the sac at the puppy’s face first, clear membranes from the nostrils and mouth with a clean cloth or your fingers, and rub the puppy firmly with a clean towel to stimulate breathing. The umbilical cord should be tied with dental floss approximately 1 cm from the puppy’s abdomen and cut on the maternal side of the tie with clean scissors. The dam typically takes over once the puppy cries and begins moving. Have clean towels, dental floss, and blunt-nosed scissors prepared before whelping begins.

My dog has been straining for 30 minutes without delivering a puppy. What should I do?

Call your veterinarian or an emergency veterinary clinic immediately. Active straining for more than 20-30 minutes without delivery of a puppy meets the veterinary criteria for dystocia – a condition that requires prompt evaluation. The puppy may be in a malpresentation, the puppy may be too large for the birth canal, or uterine inertia may have developed. Do not wait to see if the situation resolves – prolonged dystocia without intervention puts both the puppy and the dam at risk. Have the telephone number for an emergency veterinary service prepared before whelping begins.

For more veterinary-reviewed guidance on dog reproductive health and whelping, explore our Dog Health library.

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