The source I was citing is "Risk in Mother-Infant Separation Postbirth" by Gene Cranston Anderson in "Image: Journal of Nursing Scholarship", Vol 21, Number 4, Winter 1989, p196-199. "...each time the strain phase of a cry is released, poorly oxygenated blood flows through the foramen ovale and back into the systemic circulation rather than into the lungs. Thus some degree of hypoxemia must develop. Moreover this blood flow occurs in a large bolus. Thus large fluctuations in blood flow occur. Each bolus is shunted under high pressure through the foramen olvae (Lind et al 1964)............From a lifespan perspective, a patent foramen ovale was found in apparently healthy adults (18 to 35 years) with shunting occuring at rest in 5 percent and on release of the Valsalve maneuver in an additional 13 percent. Patent foramen ovale was found also in 40% of 60 adults under 55 years of age with ischemic stroke and a normal cardiac examination. These investigators concluded that paradoxical embolism through a patent foramen ovale may be responsible for stroke more often than is usually suspected." So, friends, crying may be responsible for more than just sore ears and "exercise" of the baby's lungs! Queen of the obscure facts that really need more publication! Martha Brower RD LD IBCLC and former children's librarian, storyteller and sales rep.