Dog Breeding – Physical Blockage

The two common causes of physical blockage are a very large puppy and a puppy who is not positioned correctly in the birth canal.

Oversized puppies may appear in litters with just a few puppies, and particularly in litters with a single puppy. Relatively large puppies may also appear when the sire was much larger than the dam. Prolonged gestation, and a puppy with a congenital defect such as hydrocephalus, are other reasons why a pup might be oversized relative to the size of the birth canal.

Physical blockage is often caused by a combination of a large puppy and a relatively narrow birth canal. Maternal causes of a narrow birth canal include a small pelvis, occasionally seen in terriers and the brachycephalic breeds; vaginal stenosis or a persistent hymen; a tumor of the vagina; or a previously fractured pelvis.

An incorrectly positioned puppy comes down the birth canal backward, with his hind feet or rump presenting first. Most puppies come down nose and feet first, in the diving position, with their backs along the top of the vagina. The hind foot presentation occurs about 20 percent of the time. It is probably not accurate to call this an incorrect presentation, because it seldom causes a problem.

The breech position, however, in which the rump is the presenting part, does cause problems—particularly when it occurs with the first puppy. Another presentation that can complicate delivery is when the head is bent forward or to the side.

Treatment: Physical blockage can be suspected if the mother actively strains (bears down) for more than 30 to 60 minutes without delivering a puppy, or if she exhibits weak, ineffectual labor for more than two hours instead of resting quietly between births. The obstruction must be unblocked by a veterinarian to prevent complications and allow labor to resume.

Veterinary obstetrics for an incorrect position involves manually correcting the presentation. Sterile gloves are used and the vaginal canal is lubricated with Betadine solution and K-Y Jelly. With one hand beneath the mother’s abdomen in front of the pelvis, the body of the uterus is lifted to align the puppy with the birth canal. A finger is slipped into the vagina to feel for a head, tail, or leg. A tilted head can be corrected by inserting a finger into the puppy’s mouth and gently guiding the head into correct alignment.

To correct a breech (rump first) presentation, first one leg and then the other is hooked with the finger, slipping the legs over the pelvic brim and into the vagina. This converts the breech to a hind foot presentation. The vaginal opening is gently stretched to stimulate a forceful push by the mother. When the puppy is part way out, delivery is assisted as described for assisting a normal delivery.

Occasionally a blockage is caused by a retained placenta. The placenta can be hooked with the fingers and then grasped with a sterile gauze pad. Steady traction is maintained until the placenta passes out of the vagina.

If the obstruction cannot be relieved by medical means, an emergency cesarean section is required.