Worldwide medical and scientific journal for animal health professionals
Veterinary Focus

Issue number 26.1 Other Scientific

Occurrence of congenital conditions in puppies

Published 15/03/2021

Written by Emi Kate Saito and Catherine Rhoads

Also available in Français , Deutsch , Italiano , Español and ภาษาไทย

The addition of a puppy into a household is a fun and exciting time for new pet owners. Young, playful pets present to the veterinary clinic for routine vaccinations and deworming, and most of these visits are routine and uneventful. 

Occurrence of congenital conditions in puppies


The addition of a puppy into a household is a fun and exciting time for new pet owners. Young, playful pets present to the veterinary clinic for routine vaccinations and deworming, and most of these visits are routine and uneventful. However, on occasion the veterinarian may find something out of the ordinary, a congenital condition that may need to be managed or treated. In this report, commonly diagnosed congenital disorders are reviewed and an analysis of the temporal trends for these conditions is presented.

Methods of analysis

The health records of all dogs presented at Banfield Pet Hospital in the first and last years of a 5-year period (2010 and 2014) were screened to identify those that came in as a puppy where a congenital condition was recorded. Puppies were defined as being under 12 months of age on their first visit in each year – thus, a dog that presented in January 2014 at 8 months of age, but re-presented in September at 16 months old, was counted as a puppy for 2014. The congenital disorders diagnosed in puppies are listed in Table 1 by organ system. The prevalence of the top 5 diagnoses and each organ system group for 2014 was identified, and the 2010 prevalence of each condition and system group provided for comparison. An analysis to evaluate observed temporal changes in disease prevalence was performed using a z-test to compare proportions 1.


Table 1. Congenital conditions diagnosed in 2014 at Banfield Pet Hospital.
Organ system category Congenital conditions in this category
Cardiovascular Aortic stenosis; Atrial septal defect; Cardiac septal defects; Factor VII deficiency; Hemophilia A, Factor VIII deficiency; Hemophilia B, Factor IX deficiency; Patent ductus arteriosus; Pulmonic stenosis; Tetralogy of Fallot; Ventricular septal defect; Von Willebrand's disease
Endocrine Dwarfism; Growth hormone deficiency
Gastrointestinal Cleft palate; Diaphragmatic hernia; Hiatus hernia; Megaesophagus; Megaesophagus, primary; Persistent aortic arch convolutions; Persistent right aortic arch; Pyloric stenosis; Vascular ring anomaly
Neurological Cerebellar hypoplasia; Deafness, congenital; Hepatic encephalopathy; Hydrocephalus; Nystagmus, congenital; Portosystemic shunt
Reproductive Cryptorchid (abdominal/inguinal/unspecified*), pseudohermaphrodite

* Cryptorchid (non-specified) cases are animals found to be cryptorchid, but not diagnosed as either abdominal or inguinal.


Almost 2.4 million dogs were seen in over 8 million visits at Banfield Pet Hospital in 2014, of which 540,183 (22.5%) were puppies. Table 2 lists the 5 most common congenital disorders noted for this year; the top three diagnoses were cryptorchidism (with 38.3 to 120.9 cases per 10,000 dogs diagnosed with one of these three conditions) followed by congenital deafness and portosystemic shunts. These two conditions were noticeably much rarer, with less than 9 and 3 cases per 10,000 dogs respectively. The top 5 congenital conditions did not change in rank since 2010, although (with the exception of portosystemic shunts) the prevalence for each increased from 2010 to 2014. All of the changes in prevalence were found to be statistically significant.


Table 2. Prevalence estimates for the top 5 congenital conditions found in puppies.
Diagnosis 2014
No. of cases
No. of cases per 10,000
No. of cases
No. of cases per 10,000
No. of cases per 10,000 p-value
Cryptorchidism (non-specified) 6,531 120.9 5,060 92.8 +33.3% < 0.0001
Cryptorchidism, inguinal 2,513 46.5 2,123 38.9 +19.5% < 0.0001
Cryptorchidism, abdominal 2,071 38.3 1.881 34.5 +11.0% 0.0009
Deafness, congenital 447 8.3 295 5.4 +53.7% < 0.0001
Portosystemics hunt 126 2.3 200 3.7 -37.8% < 0.0001

Reproductive conditions were more commonly diagnosed than any other congenital disorder (Table 3).Neurological conditions were a distant second and gastrointestinal and cardiovascular conditions even further third and fourth. The changes since 2010 were found to be statistically significant for the reproductive, gastrointestinal and endocrine categories. 


Table 3. Prevalence estimates of the congenital conditions by organ system category.
Organ system category 2014
No. of pets
No. of cases per 10,000
No. of pets
No. of cases per 10,000
% Change 
Since 2010
10,912 202.0 8,861 162.5 +24.3% < 0.0001
Nervous 719 13.3 689 12.6 +5.6% 0.3270
Gastrointestinal 182 3.4 256 4.7 -27.7% 0.0006
Cardiovascular 141 2.6 150 2.8 -7.1% 0.6557
Endocrine 16 0.3 5 0.1 +200.0% 0.0154

* The total numbers for cryptorchid cases in Table 2 is slightly more than the total number of dogs diagnosed with reproductive problems in Table 3, probably because in some instances a puppy was diagnosed initially as an abdominal cryptorchid, but the testicle descended to the inguinal region as the pup got older, or a non-specified cryptorchid was identified as being abdominal or inguinal at a subsequent visit.


Given the ease with which cryptorchidism is diagnosed, it is not surprising that this was the top condition identified. As Banfield hospitals are first opinion practices, it is possible that the other conditions listed in Table 1 are under-diagnosed or under-recorded, as many require referral to a specialist for further diagnostic evaluation. In addition, the review was limited by the standardized list of conditions available in the record system, so if a diagnosis is made but the condition is not listed (or is listed under a different name), the veterinarian may not record the diagnosis appropriately. Given that this study was limited to those cases where a congenital disorder was noted within the first year of life, the calculations may under-estimate the true prevalence for some disorders, as they may not be detected or appropriately diagnosed until the pet is older – the chosen age limit was for ease of data extraction and to ensure diagnosis most likely reflected a congenital origin.

The changes in prevalence estimates may reflect increased or decreased recording of a diagnosis in the Banfield system (although there is no known reason why this should be so), or they could be attributed to improved diagnostic capabilities and/or changes in evaluating breeding quality by some breeders and pet owners. It would seem that the varying prevalence does indeed reflect a genuine alteration in the occurrence of these conditions in young dogs, although the underlying reasons are not apparent.


  1. Woodward M. Epidemiology: study design and data analysis. 2nd ed. Boca Raton, FL: Chapman and Hall/CRC, 2005.

Emi Kate Saito

Emi Kate Saito

Dr. Saito qualified from the Veterinary Faculty at the University of Pennsylvania in 1997. She was awarded a Masters in Public Health by Emory University Read more

Catherine Rhoads

Catherine Rhoads

Catherine Rhoads, Banfield Pet Hospital, Portland, Oregon USA Read more

Other articles in this issue

Issue number 26.1 Published 25/03/2021

A quick guide to… Intensive care of newborn puppies

Puppies are less well developed at birth than many other species, and high mortality rates are not uncommon in the first two weeks of life.

By Renata Azevedo de Abreu and Camila Vannucchi

Issue number 26.1 Published 24/03/2021

Canine parvovirus

Canine parvovirus (CPV) is a small, non-enveloped virus consisting of a spherical capsid...

By Nicola Decaro

Issue number 26.1 Published 19/03/2021

Canine colostrum

The neonatal period is a major risk period in the dog, since approximately 20% of live-born puppies die before they are 21 days old...

By Sylvie Chastant-Maillard and Hanna Mila

Issue number 26.1 Published 16/03/2021

Anesthesia for cesarean section in the dog

The major goal in anesthesia for cesarean section (CS) is to minimize fetal effects of anesthetic drugs in order to minimize fetal respiratory...

By Bonnie Hay Kraus