SYMPTOM
Straining without delivery
A bitch or queen in labour pushing with visible abdominal contractions, sometimes grunting, raising her tail or looking round at her flank, without a puppy or kitten appearing; or a pause between deliveries that stretches on while more young are known or thought to remain.
Obstructive
Straining without delivery can reflect mechanical obstruction within the birth canal, which may occur when foetal size, position, or presentation creates difficulty passing through the pelvis. The pattern can also arise from maternal pelvic anatomy that does not accommodate the size or shape of the foetus.
Uterine
In some cases, straining occurs when uterine contractions are present but insufficient to move a foetus through the canal, a pattern termed uterine inertia, which is among the most frequently identified causes of difficult labour in bitches and queens. This can develop after prolonged labour or when the uterus becomes fatigued, stretched, or unresponsive to normal signalling.
Hormonal
The timing and strength of labour depend on coordinated hormonal signals between the mother and foetus. Disruption in this cascade, whether from incomplete maturation, placental dysfunction, or endocrine imbalance, may result in straining that does not progress to delivery.
Foetal
Straining without progression can reflect circumstances where the foetus itself is not viable or where foetal distress has altered the normal sequence of labour. Abnormalities in foetal size, conformation, or vitality can influence the mechanics and success of delivery.
Systemic
Underlying maternal conditions, such as metabolic imbalance, hypocalcaemia, or systemic illness, can affect the strength and coordination of uterine contractions. These factors may reduce the mother's capacity to sustain effective labour even when anatomy and foetal presentation are within normal range.
Why timing matters
Early observation
When straining is first observed during labour, it may represent the early phase of a process that will resolve spontaneously, or it may signal obstruction or uterine fatigue from the outset. How long she has been straining, the presence or absence of foetal membranes or fluid, and whether the animal appears distressed or calm can all inform the picture. The first stage of labour, which commonly lasts six to twelve hours in the bitch, brings restlessness, nesting, panting, shivering and sometimes vomiting, but no visible abdominal straining, and this is normal. Once pushing begins, a delivery usually follows within about half an hour of strong straining, and short rests between bouts of pushing are part of ordinary labour.
Later presentation
Once strong straining has gone on for around half an hour without a delivery, obstruction, uterine exhaustion and foetal compromise become increasingly likely, and puppies or kittens held in a stalled labour can die within hours as placental support fails. Prolonged straining can also lead to maternal fatigue, dehydration, or tissue trauma within the birth canal. Straining that fades after a long period of effort can look like a mother settling, when the uterus may instead have become exhausted with young still inside.
Labour in domestic animals typically follows a sequence of stages, and the length of each varies by species, litter size, and individual factors. In dogs and cats, intervals between deliveries can range from minutes to over an hour under normal circumstances. Patterns that deviate, such as continuous straining without any delivery, or straining that stops and starts without progression, may reflect evolving obstruction, declining uterine function, or maternal exhaustion. Individual variation is real but has limits, and continuous straining without a delivery falls outside them. A long pause with young still inside is harder to read: a queen can rest for many hours between kittens while relaxed, eating and nursing, but from the outside such a pause can be hard to tell apart from an exhausted uterus, and only an examination can show which it is.
Conditions commonly associated
Dystocia
Dystocia often presents as prolonged, unproductive contractions when obstruction or inertia prevents normal birth.
Eclampsia in Dogs
Eclampsia is a fall in blood calcium in a bitch, most often while she is nursing puppies one to four weeks old, though it can occur before or around the birth. Low calcium can weaken uterine contractions during labour, and in its clinical form it brings restlessness, panting, stiffness, tremors and a high body temperature, and can progress to seizures, with small breeds at higher risk.
Uterine Inertia
Weak or absent uterine contractions mean straining, where it happens, produces no puppy or kitten, or labour fails to move forward at all.
When to explore further
If strong, persistent straining continues for more than about thirty minutes without producing a puppy or kitten, or weak, intermittent straining goes on for two to four hours without a delivery. A puppy, kitten or fluid-filled membrane visible at the vulva that does not move forward with further pushing suggests one lodged in the birth canal. A resting interval of more than two to four hours between deliveries, with foetuses still remaining, is a separate cause for concern.
If the animal appears weak, distressed, or collapses during or after straining, or if any discharge becomes heavily bloody or foul-smelling.
If there is a known history of difficult previous deliveries, a narrow pelvis, for example after an old fracture, a very small litter with one or two large foetuses, or a very large litter that can exhaust the uterus. Brachycephalic breeds carry a high risk, and more than 80 per cent of litters in Boston Terriers, Bulldogs and French Bulldogs are delivered by caesarean section.
If straining stops entirely after a period of effort but the known number of foetuses has not been delivered, or if the abdomen remains distended.
If the mother shows signs of illness beyond the restlessness, panting and shivering of early labour, such as repeated vomiting, muscle twitching or stiffness, or disorientation.
If a dark green discharge appears in a bitch before the first puppy is born. Green discharge is expected once puppies are arriving, but before the first birth it comes from a placenta separating from the wall of the uterus, which means that puppy's oxygen supply is failing.
A labour that has stalled cannot be sorted at home into one that will resolve and one that will not. Whether a puppy or kitten is lodged in the birth canal, how many remain, and whether they are still alive and not in distress are judged by examination, radiographs or ultrasound, which can show foetal heart rates. The longer obstructed or failing labour continues, the lower the chance that the remaining young are born alive, and a mother straining against an obstruction can tire, become dehydrated or, rarely, suffer a torn uterus. Notes on when her temperature dropped, when straining began, when each delivery happened, how many have been born, the colour of any discharge and how the mother seems give whoever examines her a much clearer picture.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS