The Fetus Ejection Reflex Revisited

In this comment on the preceding paper by Michel Odent on the fetus ejection reflex, the evolution of the original Newton hypothesis of a psychoactive, neurohormonal fetus ejection reflex is discussed with reference to similarities to the milk ejection reflex. The ecologic importance of the ability of environment to regulate labor and lactation is emphasized. Four types of fetus‐expulsion mechanisms discussed by Ferguson are reviewed, with the emphasis on the need for more research. The work of Newton and her collaborators, who first experimentally demonstrated the environmental regulation of labor in an infrahuman mammal, is discussed in connection with current data on the effect of environment on human labor.