Canine Reproductive Hormones and Pregnancy Dynamics

The domestic dog exhibits a distinctive reproductive cycle dominated by a long-lived corpus luteum which secretes progesterone throughout both pregnant and non-pregnant dioestrus. Progesterone drives endometrial receptivity, supports early embryonic development and prevents uterine contractility. In the absence of pregnancy, luteolysis is delayed, often leading to pseudopregnancy characterised by anatomical and behavioural changes mimicking true gestation. When embryos implant, decidual stromal cells differentiate under the influence of progesterone and local factors, contributing to an endotheliochorial placenta. Placental syncytia and decidual cells secrete relaxin and prostaglandins, modulating luteal function, vascular adaptation and parturition timing. Prolactin becomes luteotropic after the first third of dioestrus, fine-tuning progesterone output and facilitating mammary development. The balance between pro- and anti-inflammatory mediators in the uterine microenvironment orchestrates trophoblast invasion and maternal immune tolerance. Understanding these hormonal and immunological networks has practical applications in veterinary obstetrics, breeding management and conservation of endangered carnivores, where non-invasive endocrine monitoring and targeted interventions can optimise reproductive outcomes.

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Canine Reproductive Hormones and Pregnancy Dynamics publication trend

The graph below shows the total number of articles in canine reproductive hormones and pregnancy dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Corpus luteum: Transient ovarian structure that produces progesterone following ovulation.

Progesterone (P4): Steroid hormone essential for establishing and maintaining pregnancy.

Prolactin (PRL): Pituitary hormone that supports luteal function and mammary gland development in mid-to-late dioestrus.

Relaxin: Peptide hormone of placental origin that aids in luteotrophic support and pelvic ligament relaxation.

Prostaglandin F2α (PGF2α): Lipid mediator involved in luteolysis and parturition.

Decidualization: Differentiation of uterine stromal cells into specialised decidual cells under hormonal and local signals.

Pseudopregnancy: Physiological state in non-pregnant bitches characterised by luteal persistence and signs of pregnancy.

References

1. Decidual cells and decidualization in the carnivoran endotheliochorial placenta. Frontiers in Cell and Developmental Biology (2023).
2. In vitro decidualisation of canine uterine stromal cells. Reproductive Biology and Endocrinology (2015).
3. Antigestagens Mediate the Expression of Decidualization Markers, Extracellular Matrix Factors and Connexin 43 in Decidualized Dog Uterine Stromal (DUS) Cells. Animals (2022).
4. Progesterone Concentrations during Canine Pregnancy. Animals (2021).