Establishment and Maintenance of Feline Pregnancy-A Comprehensive Review

Area of Science:

• Veterinary Science
• Reproductive Biology
• Comparative Mammalian Reproduction

Background:

• Feline pregnancy establishment has many unanswered questions, unlike in dogs.
• The feline placenta produces steroid hormones and corticotropin-releasing hormone (CRH).
• Limited data exists on uterine physiology, immune suppression, and embryo implantation in early feline gestation.

Purpose of the Study:

• To review current knowledge on feline pregnancy establishment and maintenance.
• To identify knowledge gaps in fetal-maternal signaling, uterine mechanisms, and hormonal regulation.
• To highlight areas for future research in feline reproductive physiology.

Main Methods:

• Literature review of existing studies on feline and canine reproduction.
• Analysis of hormonal profiles, placental morphology, and early gestation events.
• Comparison of feline gestation with canine gestation where applicable.

Main Results:

• Feline pregnancy lacks known feto-maternal signaling for establishment, unlike dogs.
• The placenta is a source of steroid hormones and CRH in cats.
• Progesterone and prolactin are key hormones for maintaining feline gestation, with variable effects of interventions.

Conclusions:

• Significant differences exist between feline and canine pregnancy, particularly in placental morphology and early gestation events.
• Further investigation into extracellular vesicles, anti-Müllerian hormone (AMH) function, and immune tolerance is crucial.
• Understanding species-specific sonographical markers is essential for accurate feline pregnancy monitoring.