Congrats! Your canine patient is pregnant—now what? This article provides a full overview of eutocia (normal whelping), medical and surgical treatment of dystocia (difficult birth), and, finally, postpartum conditions that may occur. While a smooth birthing process is ideal, it is key to know how to identify potential problems in case early intervention is needed to help save the life of the birthing dog and her puppies.
Gestation length varies slightly based on how you count.
If the date of luteinizing hormone (LH) surge is known, the due date is calculated as 65 plus or minus one day from that date. Similarly, if you know the date of ovulation using progesterone timing, the due date is 63 plus or minus one day. Both have very tight windows.
If you have vaginal cytology (day one diestrus), the due date is calculated as 57 plus or minus three days from that date; however, if you have a breeding date, it is 63 plus or minus seven days from the date of first breeding. This presents a two-week window within a nine-week gestation, which is a huge margin of error! Thus, we cannot rely on a breeding date alone to tell us when a bitch is overdue.
Premonitory signs of labour may include:
- A rectal temperature decrease within 24 hours of whelping, which is greater than a one-degree drop from baseline or less than 99 degrees. This temperature drop only lasts about eight hours, so it is possible to miss it.
- Extreme nesting behaviour. Some dogs will collect their toys and things throughout gestation, but when the animal is very uncomfortable (e.g. tearing bedding up), this likely represents stage one labour.
- The presence of uteroverdin (i.e. green/black vulvar discharge). This is indicative of placental separation and means a puppy should be born within about 15 minutes.
It is also helpful to understand the three stages of labour:
- Stage one begins at the start of uterine contractions (which are not typically externally visible) and ends with dilation of the cervix (which is not palpable in the dog). Typically, this stage averages about six to 12 hours, although it can last up to 24 to 36 hours.
- Stage two is delivery of the fetus. Data shows 60 per cent of fetuses are delivered in cranial presentation (‘forward’), while 40 per cent are delivered in caudal presentation (‘backward’). Both are normal as long as all limbs are extended. It should only take up to 30 minutes per fetus for delivery.
- Stage three is the delivery of the placenta. Stages two and three occur simultaneously in the bitch (as well as, in cats, the queen). Thus, it is very common to get two puppies followed by two placentas.
Some maternal predisposing factors for dystocia include:
- Physical obstruction of the birth canal (e.g. vaginal mass, vaginal stricture, vertical vaginal septum, etc.)
- Pelvic fractures which have not healed in perfect anatomical alignment—these can sometimes narrow the vaginal vault
- Breed predilection:
○ Brachycephalic breeds have cephalopelvic disproportion, which means large head and narrow hips
○ Terriers have a high rate of uterine inertia
- Obesity, both because adipocytes (i.e. fat cells) release some inflammatory cytokines, and because of physical obstruction of the birth canal if there is excess fat deposition around the vaginal vault
Additionally, some fetal predisposing factors for dystocia include:
- Fetal malposition or malposture (i.e. fetus not in cranial or caudal presentation with all limbs extended)
- Oversized fetuses or one fetus—often, singletons will grow too large to pass on their own or will not signal to the bitch when it is time to go into labour, resulting in prolonged gestation (it is estimated approximately 40 per cent of dogs will spontaneously go into labour with one fetus)
- Deceased fetuses, as these do not signal when it is time to go into labour and often do not present themselves properly
- Grossly deformed fetuses (i.e. fetal monsters)
Types of dystocia include:
- Obstructive dystocia
- Primary uterine inertia—there are a lot of documented causes for primary uterine inertia, but this is where the uterine contractions start, but fail to organize into any kind of progressive pattern that leads to fetal expulsion (there are a variety of causes that all lead to the same presentation, and all etiologies are typically treated the same)
- Secondary uterine inertia (i.e. myometrial exhaustion)
- Systemic illness or maternal compromise
- Fear and/or inexperience
- Prolonged gestation length—if more than 72 days have passed since the first breeding, a pregnant female is considered overdue (without more information than the breeding date, it is very difficult to tell if the puppies may be in trouble or not)
- Four hours after the onset of stage two labour with no puppies produced
- More than two hours between deliveries of fetuses (note: some references say four hours)
- Strong and frequent stage two labour contractions that fail to produce the puppy within 30 minutes (or do not show any progress within 15 minutes)
- Large amounts of hemorrhagic vulvar discharge at any time—while discharge is to be expected, frank blood is not normal and can be suspicious for uterine torsion (i.e. twisting of the uterus)
- Presence of uteroverdin (i.e. green or black discharge) prior to delivery of the first puppy—if uteroverdin is observed and there is not a puppy immediately forthcoming (essentially within 15 minutes or so), this may be a problem and must be investigated
- If the dam is ill or distressed at any point—while parturition is stressful, she should not be distressed
- Fetal distress noted on ultrasound (i.e. fetal heart rates slower than 180 beats per minute)
With dystocia, manipulative treatment is fairly limited by small patient size in most cases. The cervix is not palpable, so it will not be possible to tell if it is open or closed. Typically, you only need your fingers and lubrication to deliver a stuck puppy; if an instrument is required, a spay hook is a good choice. Most importantly, if progress is not made within five to 10 minutes, a C-section is indicated.
Medical management of dystocia is appropriate if:
- the dam is in good health;
- the Ferguson reflex is intact;
- no fetal maternal mismatch is noted on radiographs;
- obstructive dystocia is ruled out;
- no fetal stress is noted on ultrasound; and
- we have four or fewer fetuses remaining.
More than 80 per cent of canine dystocia is treated via C-section, as the factors listed above are often not all present. Medications utilized include oxytocin (to increase the frequency of contraction) and calcium gluconate (to increase the force of contraction). This author’s general rule is up to three injections of each before proceeding to C-section.
Ultimately, surgical management is the most common treatment of canine dystocia, and the most common indication is fetal distress. Other indications include maternal compromise and obstructive dystocia that cannot be fixed rapidly, or any kind of anatomical abnormalities that will preclude a vaginal delivery.
Clip and dirty prep the abdomen prior to induction of anesthesia. Induce with alfaxalone or propofol, ideally in the operating room with surgeons scrubbed in and the table set up. Maintain on gas (isoflurane or sevoflurane) as well. These girls have an increased risk of aspiration pneumonia because progesterone will decrease the lower esophageal sphincter tone. If an epidural can be done quickly, these are great for pain control. A fentanyl CRI or a single dose of an opioid can be used once all puppies are removed.
After delivery, there are several postpartum conditions that may occur.
Among these is SIPS, or subinvolution of placental sites. A primary symptom of SIPS includes bloody vaginal discharge, especially for longer than three weeks postpartum. Typical treatment consists of supportive care, though a blood transfusion is sometimes necessary as well. In severe cases, a spay may be required to stop the bleeding.
Metritis is a uterine infection that typically occurs postpartum. Bacteria can ascend into the uterus when the cervix is open during whelping, sometimes resulting in infection. Symptoms include a fetid discharge postpartum and, in some cases, systemic illness. Lochia is normal postpartum; however, if the discharge begins to smell, changes colour, or becomes more voluminous, metritis should be considered. Treatment typically consists of supportive care and antibiotics, though, like with SIPS, a spay may become necessary.
Hypocalcemia (or puerperal tetany) is the loss of calcium through lactation. This can also occur through fetal mineralization, but this is uncommon. Typically, this condition occurs about two to four weeks postpartum (when the demands for calcium for lactation are highest) in young, small breeds with large litters. The treatment is to give IV calcium to effect, with electrocardiogram (ECG) monitoring required during administration. Oral calcium supplementation can then be instituted.
Finally, agalactia is a postpartum condition referring to a failure of milk production. This is most commonly due to premature C-section. Typical treatment involves domperidone or metoclopramide to enhance milk production.
When it comes to canine delivery, early diagnosis of potential problems will help prevent any life-threatening emergency to both puppy and dam via timely and appropriate treatment. Having a keen understanding of eutocia, medical and surgical treatment of dystocia, and possible postpartum conditions can help set patients up for success.
Jenna Dockweiler, MS, DVM, DACT, CCRT, CVAT, graduated with honours from Kansas State University’s College of Veterinary Medicine in 2014. She completed her comparative theriogenology residency at Cornell University in 2017 and became a diplomate of the American College of Theriogenologists the same year. Dr. Dockweiler practiced small animal theriogenology and general practice for four years prior to becoming a veterinary geneticist with Embark Veterinary.