Pamela A. Davol, 76 Mildred Avenue, Swansea, MA  02777-1620.
pdavol@labbies.com

Canine Reproduction

Part 3. Medical Management of Complications Affecting Delivery (Whelping)

Complications that arise during pregnancy and whelping are infrequent but when they do occur may constitute immediate and life-threatening situations to both the dam and the puppies. Early recognition of warning signs followed by immediate medical treatment goes far in preventing fatality to the dam as well as increasing the survival of the puppies.

Warning Signs of Whelping Complications

When it is necessary to transport the bitch, any puppies that have already been whelped should be taken along. Puppies should be placed in a laundry basket or box layered with towels. Water bottles filled with "warm" water (not hot) can be placed in the basket to keep the pups warm. It is helpful to have another person do the driving so that the breeder/owner can assist the bitch if she should deliver another puppy on the way to the veterinary hospital.

Assessment of the Dam

Evaluation of the "Overdue" Bitch

In the absence of preovulatory screening for serum progesterone/LH peak, estimations of due date can be quite variable ranging from 57 to 72 days from the original breeding date. In most cases when ovulation date has not been accurately determined by serum testing, the estimated due date is usually incorrect and whelping will proceed normally once gestation is complete (63±1 days from the actual date of ovulation). In non-life-threatening situations in which a bitch is considered overdue, prior to performing cesarean delivery, serum progesterone levels should first be quantitated to prevent the possibility of surgical delivery of premature pups. High serum progesterone levels (above 2 ng/ml) would be indicative that gestation is incomplete and contraindicate the use of cesarean surgery. As a precaution, however, fetal monitoring may be employed to ensure the well-being of the fetuses (see "Fetal Monitoring" below).

Special note regarding pregnant bitches undergoing treatment for progesterone insufficiency: Bitches that are receiving exogenous progesterone therapy for treatment of insufficient luteal phase will not demonstrate a decrease in serum progesterone until therapy is discontinued. In such cases, timing of progesterone withdrawal is critical for the well-being of the puppies. Administration of progesterone must cease 2 days prior to delivery date. If progesterone supplementation is continued just one to two days past the normal gestation term, labor does not occur and the fetuses will die. Therefore, accurate ovulation date and subsequent calculation of gestation period is critical when scheduling progesterone therapy.

Management of Emergency Conditions

Time is of the essence when evaluating emergencies associated with pregnancy and whelping. Any immediate, life-threatening conditions affecting the bitch must receive priority medical attention to avoid the potential of losing the dam as well as the pups.

In instances where the bitch is not in immediate danger, a thorough evaluation will include both an assessment of the bitch and assessment of the fetuses. The veterinarian will quickly perform an examination of the bitch concentrating on the reproductive system. An internal exam will reveal whether or not a puppy is lodged in the vaginal tract. If so, the veterinarian may attempt to assist delivery if conditions are favorable (i.e. if the pup is not too large or malpositioned). If there is no evidence of obstruction, the veterinarian will continue with the examination, checking the bitches' temperature, pulse, respiration, heart rate, blood-oxygen levels (mucus membrane color and capillary refill time), hydration, and pupillary response. Palpation of the abdomen and uterus will allow the vet to determine evidence of abdominal pain (that may be indicative of uterine torsion or rupture) and evaluate the presence and positions of fetuses, respectively. The entire physical examination and evaluation of the bitch should take no more than about 5 minutes.

Fetal Monitoring. To prevent fetal mortality in cases of complicated deliveries, it is critical that fetal monitoring be performed. For this reason, it is recommended that fetal monitoring commence as soon as the initial examination of the bitch is completed (within 10 minutes of presentation at the veterinarian office). Evidence of fetal distress (indicated by heart rates lower than 150 beats per minute [bpm]) is a good indication that immediate surgical intervention utilizing cesarean section is required (in place of further diagnostics or allowing the bitch more time to progress in labor) to ensure fetal survival. Fetal monitoring is performed using transabdominal ultrasound. The chest cavities of the pups are located on ultrasound and heartbeats of each pup are counted for 15 seconds then the result multiplied by 4. Pups with heartbeats calculated above 150 bpm (ideally closer to 200 bpm) are considered to be uncompromised. If fetal monitoring indicates that none of the puppies are experiencing distress, then this will allow a window of opportunity for the veterinarian to perform further diagnostics and/or attempt a more conservative approach of assisted delivery.

Fetal monitoring is also indicated in non-emergency situations particularly in over-due bitches. Monitoring will provide assurance that the fetuses are uncompromised or identify fetal stress, which would indicate the need for immediate surgical intervention. For breeders/owners who wish to perform routine fetal monitoring at home, Veterinary Perinatal Specialties of Wheat Ridge, CO offers the WhelpWise service for monitoring uterine contractions and individual heart rates.

Diagnostic Approaches

Once fetal monitoring indicates that the fetuses are in no immediate danger, the veterinarian will have time to run further diagnostics that will in most cases identify the cause of why the labor has failed to proceed normally. Routine diagnostics include the following:

Blood work. Because many bitches may become dehydrated or hypoglycemic during delivery or may experience internal hemorrhage, blood analyses to determine packed cell volume (PCV), total protein, blood glucose, and nitrogen waste products in the blood will assist the veterinarian in diagnosing such conditions. Additionally, these tests are also helpful in identifying bitches with underlying conditions that may necessitate cesarean section even in the absence of acute delivery complications. Blood work results indicative of dehydration or hemorrhage will necessitate the use of intravenous fluid therapy.

Excessive panting during labor may result in metabolic disturbance of serum calcium levels. Even slight decreases in serum calcium can result in inefficacy of muscle contractions that may slow the progress of labor. Therefore, if the veterinarian has access to in-house serum calcium testing, this assessment is recommended. In absence of testing, but in the presence of symptoms suggestive of low calcium levels, many veterinarians will administer calcium supplement to compensate for the metabolic imbalance.

Radiographs. Ideally, two views of the abdomen by survey radiography (x-ray) are usually sufficient for determining the number, size (in relation to the dam's pelvis), and position of fetuses as well as detect fetal death (skeletal collapse). As such, radiographs are helpful for distinguishing between conditions that may be managed by conservative approaches (i.e. obstetrical manipulation, oxytocin, calcium supplementation) and those that require surgical intervention (cesarean delivery).

Management of Fetal Obstruction (Dystocia)

Use of Obstetrical Manipulation. Occasionally, the failure of labor to progress is caused by one or two puppies that cause an obstruction within the birth canal. This situation may occur when:

1) a puppy is over-sized,
2) a puppy is malpositioned, or
3) two puppies are presenting at the same time.

During the initial examination of the bitch, if a puppy is found to be obstructing the birth canal, the veterinarian will quickly determine by noting size, positioning, and strength of the bitches' contractions if assistance by manipulation of the puppy or puppies is a feasible alternative to surgical intervention. In some cases the veterinarian may be able to assist the bitches' contractions by gripping (with fingers only; forceps are not recommended) the puppy under the mandible or around the shoulders (if the puppy is presenting in the head-first position) or around the hocks or pelvis (if the puppy is presenting in the feet-first position) and applying gentle tension as the bitch pushes to expel the puppy and continuing the tension between contractions to prevent the puppy from slipping back to its previous position. When size is a contributing factor to delaying progression of birth, the vet will often gently stretch the tissues of the vaginal wall in an attempt to widen the birthing canal in front of the puppy. If the vulvar opening is too narrow, an episiotomy may be performed. The vet may also stimulate contractions by "feathering" (applying gentle, backward scrapping with a finger) the vaginal wall; this may be particularly helpful to move a puppy that may be just out of reach to a position where it may be grasped by the veterinarian. Other strategies may include elevating the bitches' forelegs and chest, which will occasionally move a puppy within reach. If two puppies are presenting at the same time, elevating the hindquarters may move the second of the puppies back into the uterus and allow room for the first puppy to proceed.

When attempting assisted delivery, if progress is not evident within 10 minutes, fetuses should be monitored for signs of distress. When fetal monitoring indicates the absence of fetal distress, then there is time for the veterinarian to make another attempt at assisting delivery. Any evidence of fetal compromise, however, contraindicates any further attempts for vaginal delivery and cesarean delivery is the recommended course of action. Additionally, because of the potential for foreign bacteria to be introduced into the vaginal canal during obstetrical manipulation and the subsequent risks of systemic infection, prophylactic antibiotics should be routinely administered to bitches in which this approach has been employed.

Use of Oxytocin. Oxytocin is a naturally occurring hormone in the bitch that induces uterine contractions. Suckling stimulates the release of endogenous oxytocin. Therefore, to increase contractions and speed-up the progress of labor, it is recommended that newborn puppies be allowed to nurse between subsequent deliveries. When endogenous levels of oxytocin are not sufficient to stimulate effective uterine contractions, exogenous oxytocin treatment is often successful in increasing the efficacy of contractions. However, certain criteria must be present for the safe and effective use of oxytocin treatment in a pregnant bitch.

Bitches that are already having strong contractions but are failing to progress through labor are unlikely to benefit from administration of oxytocin; additionally oxytocin will not induce contractions in bitches suffering from uterine inertia (inability of uterine muscles to contract due to energy depletion). Because administration of oxytocin promotes placental separation, giving oxytocin to a bitch in which the cervix has not yet dilated or in cases where a puppy is lodged in the birth canal will increase the chances of oxygen deprivation to fetuses in the uterus and may result in fetal compromise and death. Accordingly, in instances of obstruction when attempts at assisted delivery fail or in cases where fetal distress is clearly evident, there is no time for administration of oxytocin and cesarean delivery is the recommended course of action.

Use of Calcium. For proper function and response, neuromuscular tissues are dependent upon a normal balance of electrolytes within the body. In particular, uterine contractions are dependent upon adequate levels of calcium. In cases where calcium metabolism has been compromised (i.e. by inadequate diet, by dietary supplementation of a nutritionally balanced diet with exogenous calcium during pregnancy, or by extended periods of uterine contractions as seen in long deliveries), mildly depleted levels of serum calcium within a whelping bitch may inhibit the normal progression of delivery by interfering with uterine contractions; more compromised levels often present life-threatening complications in the form of tetany and seizures.

Bitches presenting with weak uterine contractions can be screened for serum calcium levels. In the absence of available, in-house calcium testing, a veterinarian recognizing symptoms representative of low-calcium levels may choose to supplement the bitch with exogenous calcium in an effort to strengthen uterine contractions. In this situation, calcium supplement will be administered by a subcutaneous injection. Because of the potential dangers associated with intravenous administration of calcium (cardiac arrhythmias and sudden death), intravenous administration of calcium is only recommended when a bitch presents with clinical symptoms of life-threatening hypocalcemia (indicated by: muscle spasms, tetany [muscle rigidity] or seizures), or if low serum calcium levels have been confirmed by laboratory analysis.

Use of Intravenous Fluids. Not all bitches that experience whelping complications will require therapy with intravenous fluids. Since dehydration can lead to fetal distress by compromising the placental exchange of oxygen and nutrients, bitches that demonstrate excessive vomiting during labor or are showing evidence of dehydration will require intravenous fluid therapy. Additionally, because surgery will lead to a hypotensive state in the bitch both during and following the procedure, bitches that undergo cesarean surgery will also require treatment with intravenous fluids.

Other Supportive Measures. Anxiety and fear are factors that may also slow the progression of labor in the bitch. It is, therefore, essential that labor proceed in a quiet and comfortable environment for the bitch. Ideally, the owner/breeder, for whom the bitch has previously established a trusted bond, should monitor the progress of the delivery. If it becomes evident that the progression of normal labor is slowing down, short, attended, leash walks to allow the bitch to urinate and/or defecate may assist in speeding-up delivery. Ice cubes and Karo syrup may also be offered to the bitch to prevent dehydration and restore depleted blood sugar levels, respectively. Larger quantities of water or food, however, should be avoided until labor and delivery are completed (in the event that emergency surgery is required). In instances of complications, transfer of the bitch to a medical facility should be made as smoothly and with as little disruption as circumstances allow.

Indications for Cesarean Section

Though conservative medical management of complications may sometimes result in successful outcome, there are some situations that require immediate surgical intervention to prevent demise of the dam, fetuses or both. The following are

Occasionally, conditions warranting elective cesarean section may be identified prior to breeding or during the pregnancy. Under such circumstances, pre-scheduling of the surgery at the end of gestation is recommended to minimize stress on the bitch and fetuses. Additionally, exact date of ovulation by serum progesterone/LH testing is recommended for accurate assessment of the due-date and prevention of surgical delivery of pre-mature puppies. If the ovulation date has not been determined, an alternative approach is to monitor daily serum progesterone concentration beginning 3-5 days prior to the earliest, "best estimated" due date. Decrease in serum progesterone levels signal the end of gestation and will provide the surgeon with some assurance that the puppies are full-term prior to proceeding with elective surgery.

Medical Management of Retained Dead Fetuses and Fetal Membranes

In instances where surgical intervention is warranted but is delayed, fetal death will occur. If the dead fetuses are not spontaneously expelled from the uterus (a process that is typically impeded for the same reasons that prohibited normal delivery), the life of the bitch will be endangered. Decomposing fetal debris within the uterus places the bitch at high risk for developing systemic bacterial infections that in the absence of treatment will lead to her death. Surgical evacuation of the uterus is the optimal method of treatment for this condition. In situations where the underlying health of the bitch contraindicates surgical intervention or the breeder/owner refuses surgical intervention, intravenous fluid therapy and administration of broad-spectrum antibiotic therapy is the alternative, but often less effective approach.

Occasionally during delivery, a vigilant breeder/owner may notice that a placenta did not follow the birth of a puppy, or the breeder/owner may be unsure given the fact that sometimes the placenta is retained, later passed, but consumed by the bitch before the breeder/owner is aware. In many bitches, one or two retained membranes will not result in any clinical problems, however, in others infections may result. Typically, a bitch with retained membranes will have a heavier than normal bloody discharge subsequent to the completion of delivery. For those breeders/owners who prefer to monitor the bitches' condition in lieu of seeking immediate medical intervention, continual monitoring of the bitches' rectal temperature and examination of the vaginal discharge for any evidence of foul-smelling or pus-like material is advisable. Sudden lethargy, fever, or loss of appetite are considered warning signs that are usually indicative of a bacterial infection. Because severe systemic bacterial infection may result in some bitches, it is perhaps a good practice that all bitches known or suspected to have retained fetal membranes receive treatment for this condition.

Once radiographs have been taken to confirm that all the puppies have been delivered, administration of exogenous oxytocin will usually induce the delivery of retained membranes. Because the membranes may be delivered within a variable amount of time following administration of oxytocin and consumed by the bitch, it is not always feasible for a breeder/owner to be sure that the membranes have been passed. Therefore, prophylactic administration of antibiotics over a 7 to 10 day period and continued monitoring of the bitch for warning signs of infection (as indicated above) is typically the preferred approach for management of this condition. Cephalosporin is a broad-spectrum antibiotic typically used in this situation because it demonstrates efficacy against numerous bacterial strains and appears to be safe to nursing puppies.