The aim of the work was to describe the profile of steroid hormones in the peripartum period of the bitch. Twenty-five healthy pregnant bitches presented for pregnancy monitoring and parturition assistance were included in the study. A blood sample was collected for routine progesterone assay, and serum was stored at −20°C. The day of parturition and the number of delivered puppies were registered. Concentrations of corticosteroids, androgens, progestogens, estrogens, for a total number of 17 different hormones, were measured using ultra-performance supercritical fluid chromatography–tandem mass spectrometry. Data were analyzed using a repeated measure, mixed-model approach, taking into account day (from day −4 to day +2 from parturition), age, parity (primiparous vs pluriparous), number of delivered puppies (<4 vs 4–8 vs > 8), and interactions between factors. Day related to parturition significantly affected the concentration of progesterone (P < 0.001), testosterone (P < 0.001), 17α-hydroxyprogesterone (P = 0.0002), and cortisone (P = 0.006). Estrogen concentration did not show any significant variation over time. Testosterone and androstenedione showed an abrupt decline on the day of parturition. The concentration of all glucocorticoids increased the day before parturition. Age or parity was not significantly associated with any of the steroids. Litter size significantly affected concentrations of aldosterone (P = 0.02) and etiocholanolone (P = 0.01). Aldosterone concentrations were higher in litters with 4 to 8 pups than in litters with more than 8 pups (P = 0.02). None of the steroids measured in our study, with the already known exception of progesterone, shows potential to be clinically useful in predicting the onset of parturition in the bitch.

这项工作的目的是描述母犬围产期类固醇激素的分布。该研究包括了 25 只用于妊娠监测和分娩协助的健康怀孕母犬。采集血样用于常规孕酮测定，血清储存于-20°C。记录分娩日期和交付的幼犬数量。使用超高效超临界流体色谱 - 串联质谱法测量皮质类固醇、雄激素、孕激素、雌激素的浓度，共 17 种不同的激素。使用重复测量、混合模型方法分析数据，考虑天数（从分娩后的第 -4 天到第 +2 天）、年龄、胎次（初产与多产）、交付的幼犬数量（<4 与 4-8对比 > 8), 以及因素之间的相互作用。与分娩相关的日子显着影响了孕酮的浓度（P < 0.001)、睾酮 ( P < 0.001)、17α-羟基孕酮 ( P = 0.0002) 和可的松 ( P = 0.006)。随着时间的推移，雌激素浓度没有表现出任何显着的变化。睾酮和雄烯二酮在分娩当天突然下降。所有糖皮质激素的浓度在分娩前一天都增加了。年龄或胎次与任何类固醇都没有显着相关性。窝产仔数显着影响醛固酮 ( P = 0.02) 和乙胆醇酮 ( P = 0.01) 的浓度。4～8只幼仔的醛固酮浓度高于8只以上仔猪（P= 0.02）。我们的研究中测量的所有类固醇，除了已知的黄体酮之外，都没有显示出在临床上预测母犬分娩开始的潜力。