In the canine species, the precise mechanisms of pregnancy maintenance and the initiation of parturition are not completely understood. The expression of genes encoding the receptors for estrogen (ERα mRNA) and oxytocin (OTR mRNA) was studied in the endometrium and myometrium during pregnancy and parturition in dogs. Real-time PCR was performed to quantify the levels of ERα mRNA and OTR mRNA in...

Accurately predicting parturition in cows can be difficult because of the variability in gestation length and uncertainty of the time of parturition. The goal of the present study was to determine the electrolyte concentrations of prepartum mammary secretions of gravid cows and to investigate retrospectively the possible predictive relationships between these concentrations and the time of part...

We tested the hypotheses that 1) epidural anesthesia at parturition would block both peripheral and central release of oxytocin and eliminate the development of maternal behavior in primiparous heifers and 2) estradiol priming, genital stimulation, and appropriate neonatal stimuli would induce maternal behavior in nulliparous heifers. In experiment 1, primiparous crossbred heifers (n = 13) with...

KEY POINTS Older pregnant women have a greater risk of operative delivery, still birth and post-term induction. This suggests that maternal age can influence the timing of birth and processes of parturition. We have found that increasing maternal age in C57BL/6J mice is associated with prolongation of gestation and length of labour. Older pregnant mice also had delayed progesterone withdrawal a...

Clinical examination and emergency care in newborn puppies is difficult, due to their different physiological characteristics and needs from those of adult dogs. This paper reviews the physiological events during parturition and the influence of parturition on puppy health.

To study the temporal relationship between changes in hormone levels with the development of myometrial gap junctions, rats were sacrificed to collect uterine vein blood and uterine tissues daily from Day 15 to Day 20 of pregnancy, every 3 h on Day 21, during delivery, and 3 h after parturition. Levels of progesterone, estradiol and prostaglandin F2 alpha (PGF2 alpha) were measured by specific ...

OBJECTIVES The "dysregulated parturition" narrative posits that the human stress response includes a cascade of hormones that "dysregulates" and accelerates parturition but provides questionable utility as a guide to understand or prevent preterm birth. We offer and test a "strategic parturition" narrative that not only predicts the excess preterm births that dysregulated parturition predicts b...

The process of parturition involves the complex interplay of factors that change the excitability and contractile activity of the uterus. We have compared the relative gene expression profile of myometrium from rats before parturition (21 days pregnant) and during delivery, using high-density DNA microarray. Of 8,740 sequences available in the array, a total of 3,782 were detected as present. F...