Ferguson Reflex
Pronunciation: FUR-guh-son
A neuroendocrine reflex involving oxytocin release triggered by cervical and vaginal stretching during labor. Important consideration for timing of neuraxial anesthesia.
Full Definition
The Ferguson reflex, also known as the fetal ejection reflex, is a positive feedback mechanism crucial to the normal progression of labor. When the fetal presenting part stretches the cervix and lower uterine segment, sensory signals travel via the pelvic and hypogastric nerves to the hypothalamus, triggering oxytocin release from the posterior pituitary. This oxytocin causes stronger uterine contractions, which further stretch the cervix, creating a positive feedback loop that intensifies until delivery. In obstetric anesthesia, understanding this reflex is essential because neuraxial blocks can interfere with the sensory component, potentially affecting the natural progression of labor and requiring augmentation with synthetic oxytocin.
Usage
Usage note: Capitalize when referring to the specific reflex named after Dr. Ferguson.
In Context
- "The epidural may blunt the Ferguson reflex, necessitating oxytocin augmentation during the second stage of labor." — Anesthesia consultation note
- "Understanding the Ferguson reflex helps explain why some patients require labor augmentation after neuraxial blockade." — Medical textbook