Ectogenesis and Artificial Uterus Technology in Large Animals: Scientific Progress, Veterinary Applications, and Biotechnological Prospects

Abstract

Ectogenesis — the gestation of a mammalian fetus entirely outside the uterus, in an artificial environment — has transitioned from science fiction to laboratory reality over the past decade, driven primarily by the urgent medical need to improve survival and developmental outcomes for extremely preterm human infants. The landmark 2017 publication by Partridge et al. demonstrating that extremely preterm fetal lambs (equivalent to a 23- week human gestation) could be maintained for up to four weeks in a fluid- filled, pumpless extracorporeal circuit (the 'Biobag') while exhibiting normal brain and lung development, marked a pivotal moment in reproductive medicine and animal biotechnology. In the years following this demonstration, incremental improvements in circuit design, fluid composition, infection control, and physiological monitoring have extended the achievable support duration and expanded the technology to piglets and other species. This review comprehensively examines the scientific foundations of artificial uterus technology, including the physiology of fetal circulation, the role of amniotic fluid in fetal lung and gastrointestinal maturation, the engineering requirements of pumpless extracorporeal circuits, and the composition of artificial amniotic fluid. The veterinary and livestock biotechnology applications of artificial womb technology — including rescue of extremely preterm livestock neonates (foals, calves, lambs, piglets) that would otherwise be non- viable, gestation of embryos from critically endangered species, and the hypothetical prospect of fully artificial gestation for production purposes — are systematically evaluated. Ethical, regulatory, and societal considerations relevant to the application of this technology in livestock are also addressed. The review concludes with a technology roadmap for the next decade, highlighting the convergence of artificial wombs with synthetic biology, organ- on- chip technology, and AI- based physiological control systems.