In 1940 James Ferguson (a Canadian) established the hormonal basis of a major reflex controlling childbirth. As early as 1932, his final year of medical school, he had wondered whether there was a connection between the contractions of labour and "the posterior pituitary hormone, oxytocin" for which no function had yet been discovered. During his two-year assistant professorship at Ohio State University between 1936 and 1938, Ferguson and endocrinologist Hans Haterius found that electrical stimulation of the pituitary gland of anaesthetized rabbits produced "definite, and at times enormous" increases in uterine activity. Ferguson continued this research after his appointment to the pharmacology department at Toronto in 1938, and two years later successfully demonstrated that dilatation (stretching) of the cervix augments uterine activity by augmenting oxytocin secretion. This discovery, which became known as Ferguson's reflex, has important implications for the management of labour as the use of epidural anaesthetics interferes with this reflex, resulting in longer labours and an increased incidence of forceps delivery.

Dr. William Camman informs me that the necessity to wait for an arbitrary cervical dilatation before an epidural is instituted is bunk.

The article that "debunked" this notion appeared in the New England Journal of Medicine and was accompanied by an editorial by Dr. Camman.

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