Diagnosis of canine fetal health by ultrasonography

The detection of fetal pathology is important for the care of puppies in the postnatal period. The objective of this study was to identify parameters of fetal distress by determining fetal heart rate and bowel movements, and also to detect early pathology by means of fetal biometry, which involves determination of the biparietal and abdominal diameters. Ultrasonographic examinations were carried out on 30 pregnant bitches of different breeds and ages at least three times, including examination at days 40-47, days 48-57, and days 58-62 after coitus, and subsequently every 12-14 h for 3 days before parturition. Fetuses that had biparietal:abdominal diameter ratios of < 2 at the second and third series of ultrasonography, or after birth were considered to have intrauterine growth retardation. The average weight of each litter was calculated and puppies that weighed < 20% of the average weight were also considered to have experienced intrauterine growth retardation. Intrauterine growth retardation occurred in 39.6% of the bitches studied. Fetuses were considered to be normal when heart rate, determined by a Doppler flowmeter was > 220 beats min-1; suffering from slight fetal distress when heart rate was between 180 and 220 beats min-1; suffering from severe fetal distress when heart rate was < 180 beats min-1. Some level of distress was observed in 33.0% of puppies. In 86.7% of bitches, bowel movements were observed in at least one puppy, and appeared to be correlated with fetal distress. Bowel movements were observed in all of the puppies that had severe fetal distress (heart rate < 180 beats min-1), whereas bowel movements were observed in only 40.0% of puppies with slight fetal distress (heart rate 180-200 beats min-1). In conclusion, ultrasonographic evaluation allowed identification of fetuses with intrauterine growth retardation, and bowel movements were a reliable indicator of fetal distress; these conditions are presumed to indicate a greater perinatal risk.