Wednesday, June 30, 2010

Preterm labour

This document, Neuro-endocrinology Briefing 35: Preterm labour is available online at the British Society for Neuroendocrinology.

The briefing was sent to me by my friend and mentor, Wolfgang Jochle, who lives in New Jersey, USA. Wolfgang's life work has focused on understanding the physiology of animal reproduction. A conversation with Wolfgang always extends my thinking, even though my education in the biological sciences is very limited.

My interest in the topic of preterm labour was heightened just this morning, as a colleague and I discussed a recent experience of working with a woman in spontaneous labour at 35 weeks' gestation. The timely arrival (by air-snail-mail) of this document in today's mail was just one of life's interesting coincidences.

Here's a brief excerpt ...
"But why is birth difficult to delay long enough to reach term? The answer may lie in the recruitment of the oxytocin neurones which, once primed by the initial signals, then respond to any small trigger (including uterine factors/contraction and or psychological situations such as stress that activate parallel brain pathways). This results in an ever-increasing positive feedback that promotes oxytocin secretion in larger pulses which inevitably precipitate further uterine contraction and birth. So, far from uterine mechanisms sustaining labour, brain activity is crucial, and drugs targeting oxytocin neurone priming mechanisms may be an appropriate way forward for therapeutic intervention in preterm labour." (Author: Dr Alison J Douglas, Edinburgh, UK)

A midwife working with healthy, socially well supported, well nourished women planning homebirth does not see much preterm labour. In fact we worry more about pregnancies that extend beyond 42 weeks. (I wonder if the science of neuroendocrinology has a physiological explanation for prolonged pregnancy?)

The time, and nature, of the onset of labour hold many mysteries. The image of "ever-increasing positive feedback that promotes oxytocin secretion in larger pulses" fits well with my understanding of the vastly varied experiences women have as they approach that tipping point, which means their baby will soon be born.

A midwife is conscious of this intricate balance of physical and psychological factors in birthing.

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