Blood calcium, glucose and haematology profiles of parturient bitches diagnosed with uterine inertia or obstructive dystocia

Abstract

Bitches with dystocia most often present with clinical signs of uterine inertia (UI). The aetiology of myometrial dysfunction in most of these cases is still not elucidated. We compared blood ionized calcium (iCa) and glucose concentrations in bitches diagnosed with primary UI (PUI, n = 14), secondary UI (SUI, n = 6) or obstructive dystocia (OD, n = 6), and we described their haematology profiles. Bitches diagnosed with UI had a patent birth canal and delivered no puppies yet (PUI) or only part of the whole litter (SUI). The OD group had no UI and showed strong abdominal contractions. Blood iCa did not differ between the PUI, SUI and OD groups and was not influenced by litter size. There was a significant positive relationship (R = .241, p = .013) between iCa concentrations and the dam's body weight. Glucose concentrations were also not significantly different between dystocia groups or influenced by body weight and litter size. Hypocalcaemia was detected in 11 bitches, and hypoglycaemia in two bitches. Pregnancy-associated anaemia was seen in about one-third of the bitches. Eight of 12 dogs had increased platelet counts, and ten had leukocytosis with mature neutrophilia. Although iCa did not differ between dystocia groups, low concentrations may have contributed to the development of UI in some of the small size bitches. Hypoglycaemia was uncommon, and therefore, we consider low glucose concentrations not to have played an important role in the pathogenesis of UI in our study population. Pregnancy-associated anaemia, thrombocytosis, leukocytosis and mature neutrophilia were common findings in otherwise healthy bitches diagnosed with different forms of dystocia.

Do uterine PTGS2, PGFS, and PTGFR expression play a role in canine uterine inertia?

“…Currently, our knowledge about the underlying aetiology of canine PUI is still very limited and most studies refer to hormones and metabolic blood parameters, such as progesterone, oxytocin, calcium, and glucose (Bergstrom et al 2010;Bergström et al 2006b;Davidson 2011;Frehner et al 2018;Hollinshead et al 2010;Kraus and Schwab 1990;Lucio et al 2009). PUI is characterized by inadequate/insufficient uterine contractions, and PTGS2 and prostaglandins play an essential role in the coordination of uterine contractions (Challis et al 2002;Noakes et al 2009, Senior et al 1991Senior et al 1993;Senior et al 1992).…”

“…All dogs were assigned to one of the respective groups based on history and clinical findings as follows (Frehner et al 2018):…”

“…parturition (Hollinshead et al 2010). Other causes have also been postulated to predispose to uterine inertia such as systemic disease of the bitch, small litter size (e.g., single-pup syndrome), overstretching of the myometrium due to a large litter or excessive foetal fluids, obesity and fatty infiltration of the myometrium, hypocalcaemia, hypoglycaemia, nutritional imbalance, age-related changes, or genetic inheritance (Frehner et al 2018;Kraus and Schwab 1990;Linde Forsberg and Eneroth 2000;Linde Forsberg and Persson 2007;Simões et al 2016).…”

Diagnostic imaging: an essential tool in the successful management of canine dystocia

“…The exact aetiology of this condition is unknown, but associations have been made with a lack of circulating oxytocin, elevated progesterone, hypocalcaemia and genetics. 4 In the case of brachycephalic breeds, a large head in relation to a narrow pelvis appears to be the main reason for obstructive dystocia. Recent computed tomography studies of bulldogs showed an overall shorter pelvis and pelvic canal and a narrower pelvic outlet, which are likely to contribute to the high risk of dystocia found in this breed.…”

“…The most common reason for dystocia in all breeds appears to be uterine inertia – the failure for the uterus to appropriately contract. The exact aetiology of this condition is unknown, but associations have been made with a lack of circulating oxytocin, elevated progesterone, hypocalcaemia and genetics 4 …”