Childbirth without surprises

Science, statistics and practical advice for responsible owners

Birth is, by definition, a natural physiological process, regulated by complex hormonal and neuromuscular mechanisms. However, just because it is natural does not mean that it is always easy or risk-free. In dogs and cats, each pregnancy and birth is unique: breed, age, previous reproductive experience, litter size and even the animal’s temperament all have an influence.

From a scientific point of view, we know that the average length of gestation is around 63 days from ovulation in dogs and between 63 and 65 days in cats, but these figures can vary by several days without there being any pathology. In fact, one of the most reliable signs for anticipating the onset of labour is not the calendar, but physiology: in many bitches, a sharp drop in body temperature to values close to 37 °C is observed between 12 and 24 hours before delivery, a direct consequence of the pre-delivery decrease in progesterone. Measuring rectal temperature in the last days of gestation can provide the owner with an objective and reassuring reference point.

Understanding how a normal birth progresses allows for a balanced approach: neither intervening unnecessarily nor remaining passive in the face of an abnormal situation. In practice, this means preparing in advance a quiet environment, a comfortable whelping box and clean equipment, as well as having a clear plan of action in case of doubt. This foresight is not exaggerated: clinical studies show that up to 28% of canine births can present some degree of dystocia, the most common cause being primary uterine inertia, i.e. insufficient contractions to expel the puppies.

The three stages of the journey: normal stages of labour in dogs and cats

From a medical point of view, birth is divided into three distinct stages, each with characteristic clinical manifestations. Knowing these stages allows you to correctly interpret what is happening and make decisions based on objective criteria.

The prelude to birth: uterine dilation phase

The first stage corresponds to the dilation of the cervix and the preparation of the birth canal. It usually lasts between 6 and 12 hours, although in first-time mothers it can last up to 24 hours without being pathological.

During this period, uterine contractions occur that are not yet visible externally, but the mother usually shows restlessness, panting, slight tremors, vocalisations and a desire for isolation. These behaviours are mediated by the action of oxytocin and prostaglandins. Allowing the female to choose her place of birth, reducing external stimuli and avoiding unnecessary manipulation promotes proper physiological progression, as stress raises cortisol, a hormone that can slow down the progress of labour.

The decisive moment: expulsion phase

The second stage begins with visible and active abdominal contractions, culminating in the birth of the offspring. Under normal conditions, each puppy or kitten should be born at approximately 15- to 60-minute intervals.

During prolonged labour, the tissues of the birth canal can become inflamed and lose elasticity. This tissue fatigue reduces the effectiveness of each contraction and increases friction, leading to blockages even with correctly positioned foetuses. This is one of the reasons why time is a critical factor in obstetrics. 

Here, careful observation is key. Studies on neonatal mortality have shown that when the interval between two births exceeds 60–65 minutes, the risk of foetal or neonatal death increases significantly due to foetal hypoxia, a lack of oxygen caused by prolonged or ineffective contractions. Therefore, noting the time of each birth mentally or in writing is not an anecdotal gesture, but a simple clinical tool that helps to decide when it is prudent to intervene.

During this phase, most mothers spontaneously break the amniotic sac and stimulate the newborn’s breathing by licking it. Only if this does not occur may it be necessary to gently dry the newborn with a clean towel. Forcing the birth of a calf is never recommended: a stuck calf may indicate obstructive dystocia, and improper handling can cause serious injury.

From a scientific point of view, it has also been observed that longer or more difficult births are associated with alterations in maternal behaviour during the first 72 hours postpartum, with less attention to the young and poorer stimulation of suckling, which can indirectly affect their survival.

The end of the process: delivery phase

The third stage corresponds to the expulsion of the placentas or foetal appendages, which can be eliminated after each birth or at the end of labour. Both situations are considered normal.

Although placenta ingestion is instinctive behaviour, it is not always necessary to allow it. Excessive consumption can cause digestive disorders. It is useful to keep an approximate count of placentas expelled, as placental retention increases the risk of postpartum uterine infections.

When something is wrong: warning signs that require veterinary consultation 🚨

Although many births proceed without complications, the figures show that obstetric problems are not uncommon. In dogs, it is estimated that dystocia affects approximately 5–28% of births, depending on the breed and population studied. In purebred cats, the incidence is even more striking: between 10 and 15% require veterinary assistance, and about one in ten litters end in caesarean section, especially in breeds with particular body conformation.

Clear reasons for urgency include intense contractions lasting more than 30 minutes without birth, or intervals of more than two hours between births when expulsion efforts persist. The appearance of dark green discharge without immediate birth may indicate placental abruption and serious risk to the foetuses.

Medical fact · Secondary uterine inertia is more common than believed

Many guardians are familiar with primary uterine inertia (weak contractions from the outset), but in clinical practice, secondary uterine inertia is very common, in which labour begins normally and contractions cease after several births. This phenomenon explains why some births were ‘going well’ and suddenly stall.

In these cases, clinical experience shows that many complications are not worsened by the initial condition, but rather by delays in decision-making. Preparing transport in advance, knowing which hospital to go to, and acting quickly can make the difference between a favourable outcome and a life-threatening emergency. Clinical studies agree that delaying the decision to perform a caesarean section significantly increases foetal mortality. It is not the surgery itself that worsens the prognosis, but the prolonged period of hypoxia and prior exhaustion. Therefore, in obstetrics, ‘waiting a little longer’ is rarely neutral.

Accompanying with respect: how to help without interfering too much 🤍

Good birth support begins long before the birth. Preparing a calm, warm, and clean environment reduces maternal stress and promotes the proper release of oxytocin. Having clean towels, gloves, and a gentle heat source for newborns provides security without encouraging excessive intervention.

Did you know? · Environmental stress can cause functional dystocia

Not all dystocia is mechanical. Sudden changes in environment, the presence of strangers, loud noises or repeated attempts at manipulation can cause a reflex inhibition of oxytocin, blocking uterine contractions even though everything is anatomically ready for birth.

From a statistical point of view, it is also worth noting that very small litters (fewer than five puppies) or very large litters (more than nine puppies in bitches) are associated with a higher risk of dystocia and neonatal mortality. These extremes can alter the effectiveness of uterine contractions or cause maternal exhaustion before delivery is complete.

Having the telephone number of your vet or an emergency clinic to hand is not a cause for alarm, but rather a sign of responsibility. In veterinary obstetrics, anticipation and the ability to react are as important as patience.

📌 Key idea to remember

Knowing the physiological rhythm of labour allows you to distinguish between a normal process and a risky situation. Observing carefully and relying on objective data helps you make better decisions. Many dystocias occur in “unplanned” births, or rather, in unplanned pregnancies, where the exact date and number of foetuses were unknown and there was no prior preparation. Lack of anticipation is an indirect but very real risk factor in problematic births.

A single stuck puppy or a dystocia that is not detected in time can compromise the survival of the entire litter and the life of the mother. The clinical evidence is clear: anticipation and early consultation save lives.

Frontiers in Veterinary Science – Canine and Feline Reproduction (2023) – Reproductive performance and outcomes after caesarean section in dogs and cats. – Frontiers in Veterinary Science – Retrospective study analysing fertility after natural birth and caesarean section in dogs and cats, demonstrating high rates of successful pregnancy after obstetric interventions when there are no underlying uterine pathologies – https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2023.1120320/full

García-Mitacek, M. C. (2011) – Prospective clinical study of eutocic and dystocic birth in dogs. – Complutense University of Madrid (Doctoral thesis) – Clinical and statistical analysis of thousands of canine births establishing the actual incidence of dystocia and its main maternal and foetal causes – https://dialnet.unirioja.es/servlet/tesis?codigo=311107

Concannon, P. W., England, G., Verstegen, J. (2001) – Factors influencing neonatal mortality in bitches. – Journal of Small Animal Practice – Study linking prolonged intervals between births to increased neonatal mortality due to foetal hypoxia and uterine exhaustion – https://www.clinvetpeqanim.com/index.php?art=130&pag=articulo

Sontas, B. H., Kırlangıç, L., Turna Yılmaz, Ö. (2022) – Ease of whelping and maternal behaviour in dogs. – Scientific Reports – Research introducing the concept of ease of whelping and demonstrating the relationship between difficult births and maternal behavioural changes during the immediate postpartum period – https://www.nature.com/articles/s41598-022-10707-w

Jirkof, P., Reichler, I. M. (2019) – Incidence and causes of dystocia in pedigree queens. – Animals Health / Veterinary Reproduction – Epidemiological study demonstrating a higher incidence of dystocia and caesarean section in purebred cats, with significant differences between breeds – https://www.animalshealth.es/mascotas/descubren-partos-dificiles-gatas-pedigri-son-mas-habituales-pensaba

Concannon, P. W. (2011) – Reproductive cycles of the domestic bitch. – Clinical Veterinary Reproduction – Detailed review of canine reproductive physiology describing the drop in progesterone and decrease in body temperature as reliable markers of the onset of labour – https://ddd.uab.cat/pub/clivetpeqani/11307064v14n4/11307064v14n4p223.pdf