Transitory thrombocytopenia in newborn mice after intrauterine hypoxia.
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Abstract
Pregnant mice were exposed to hypobaric hypoxia (0.7 atmospheres) continuously during days 13 to 20 of pregnancy. In the newborn offspring, the body weights were decreased, and liver weight/body weight ratios were increased compared to nonhypoxic control animals (P < 0.001). After intrauterine hypoxia, the newborn animals were polycythemic, and a postnatal transitory thrombocytopenia lasting 7 days occurred. A rebound thrombocytosis appeared on days 13 to 15 after birth. Bone marrow megacaryocyte concentrations were increased in the hypoxic animals on days 5 to 15 after birth compared to the nonhypoxic controls. These findings may be explained by a competitive mechanism on common stem cells. Increased demand for erythropoiesis during hypoxia may shunt hematopoietic cells in direction of erythropoiesis at expense of thrombopoiesis.