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The Whelping Bitch: normal events and problems

Canine whelping is a natural process that usually goes smoothly but problems can occur. Reasons for problems with birth, their diagnosis, and monitoring are discussed here.

What characterizes normal canine whelping?

Parturition is the term for whelping in bitches. There are three recognized stages:

Stage I parturition in the bitch normally lasts from 12 to 24 hours, during which time the uterus has contractions of increasing frequency and strength, at the same time as cervical dilation. No abdominal effort (visible contraction) is evident. Bitches may exhibit changes in disposition and behavior, such as becoming reclusive, restless, and nesting intermittently. They may refuse to eat and sometimes vomit. Panting and trembling may occur. There may be clear and watery discharge from the vulva (external genital organs).

Stage II parturition begins when external abdominal effort can be seen, accompanying uterine contractions resulting in the delivery of a puppy. Typically, these efforts should not last longer than one to two hours between puppies although great variation exists. The entire delivery can take between 1 and 24 hours. Increased puppy survival is associated with shorter total delivery time (less than 12 hours) and an interval of less than two hours between puppies. Any vulval discharge can be clear to bloody. Typically bitches continue to nest between deliveries and may nurse and groom puppies intermittently. Loss of appetite, panting, and trembling are common.

Stage III parturition is the delivery of the placenta. Bitches typically shift between stages II and III of parturition until the delivery is complete. During normal parturition, all fetuses and placentae are delivered vaginally, although they may not be delivered together in every instance.

What is dystocia?

Dystocia is in the inability to expel a puppy through the birth canal. It is not uncommon in the bitch and can have several causes. The diagnosis of dystocia should be made and treatment instituted as quickly as possible to save the puppies' lives. An incorrect diagnosis of dystocia may result in an unnecessary Cesarean operation but failure to recognize or prioritize dystocia usually results in the loss of puppies and perhaps the dam.

The five main criteria indicative of dystocia

Dystocia can occur due to problems with the dam's uterus or birth canal or with the unborn puppy. The diagnosis of dystocia can be based on the presence of any of the following criteria:

Prolonged gestation. Bitches can be considered to have prolonged gestation if the pregnancy lasts longer than 70-72 days from the first breeding, 58-60 days of diestrus (metestrus) or 66 days from the day of the LH surge or initial rise in progesterone during estrus (known if ovulation timing was performed). Prolonged gestation results in oversized puppies that will not fit through the birth canal. Partial separation of the placenta can result in death of these puppies in the uterus.

Failure of the dam to proceed through parturition normally. Parturition should begin within 24 hours of a decline in body temperature below 37°C (99°F) and progress through the three stages to completion within 12-24 hours.

Failure of the dam to complete delivery of all puppies in a timely fashion. Delivery should occur within one hour of active parturition (visible abdominal efforts) or four to six hours intermittent parturition.

Foetal distress. This is due to unborn puppies with slow heart rates or stillborn.

Maternal distress. This occurs with excessive pain or systemic illness. It may be manifested by green or copious vulval discharge and/or bleeding.

Causes and treatment of dystocia

Uterine abnormalities include uterine inertia (flaccidity of the uterine muscles), abnormalities associated with fetal or maternal fluids and herniation or torsion of a uterine horn. Uterine inertia (failure of the uterine muscle to contract in an effective manner) can be primary or secondary. Bitches exhibiting primary inertia fail to ever start an effective parturition pattern and a Cesarean operation must be performed. Bitches exhibiting secondary inertia fail to complete delivery of all puppies due to exhaustion of the uterine muscle. Medical management can be attempted, with adequate fetal monitoring, but a Cesarean operation may still be necessary. Intravenous glucose containing solutions and subcutaneous oxytocin and calcium injections can be administered in appropriate doses with appropriate monitoring. Oxytocin should only be administered with veterinary guidance because it can compromise the puppy's blood supply and lead to rupture of the uterus.

Disorders of the birth canal include pelvic abnormalities such as narrowing from a healed fracture and abnormalities such as vaginal strictures. Bitches with unusually small vulvar openings may require a partial episiotomy (surgical incision) to deliver puppies vaginally.

Puppy abnormalities include puppy oversize, congenital anomalies and abnormal position, presentation or posture. Puppy oversize can occur with prolonged gestation in abnormally small litters and is a common cause of dystocia. Congenital anomalies such as anasarca and hydrocephalus (abnormalities of body fluid distribution) can cause a mismatch between the size of the birth canal and the puppy. Because both an anterior (head first) and posterior presentation is normal in the dog, only a transverse (sideways) presentation is associated with dystocia and is rare. Puppies that are born in a posterior presentation are not breech; this refers to a posterior presentation with the hind limbs flexed cranially (i.e. the puppy is born bottom first). Puppies are normally positioned with the fetal backbone adjacent to the top surface of the uterus. Malpositioning (a puppy's abdomen adjacent to the top surface of the uterus) can cause a mild dystocia. Abnormalities of posture, the normal being fully extended in a diving position, are another frequent cause of dystocia. Malpositioning of the head, forelimbs or hind limbs of the canine puppy is not readily corrected with the use of forceps, traction or digital manipulation because of the limitations of the size of the birth canal of the bitch.

How is dystocia diagnosed?

Your veterinarian's diagnosis of dystocia is based on taking an accurate history about ovulation timing and breeding dates, as well as any events surrounding labor, and by performing a careful physical examination, which will include a digital pelvic examination for any vaginal abnormalities or the presence of a puppy in the birth canal X-rays can be very helpful in assessing puppy viability, litter size and puppy position. Blood tests to measure calcium and glucose levels are helpful in identifying metabolic disorders contributing to dystocia. A uterine monitor can be used to evaluate the quality of uterine contractions.

Conclusion

With help from your veterinarian, your bitch should be able to produce a healthy litter of puppies. Early diagnosis of problems will help prevent any life-threatening emergency to puppy or dam so that suitable and timely treatment can be provided.

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