Twilight zone for babies inside womb

Babies - both human and animal - react to touch, sound and other external stimuli in the womb, but do not consciously experience them, says a group researching animal welfare.

Professor David Mellor, of Massey University, said this week that the embryo and foetus were apparently never conscious and spent much of their time anaesthetised.

"Consciousness appears only after birth, associated with exposure to air, gravity, hard surfaces, unlimited space and to cold ambient conditions."

Professor Mellor, director of the university's animal welfare science and bioethics centre, said he had made a fresh evaluation of consciousness in the womb, particularly in sheep, after meatworkers at a slaughter plant expressed concern that foetuses of slaughtered animals might be drowning in their amniotic fluid.

He said the study used extensive research into sheep which had been originally intended not for animal welfare purposes, but because sheep were an excellent large-animal "model" for humans.

A collaboration with Auckland University's foetal physiology and neuroscience group produced insights relevant to human foetuses.

He will present a major paper to a London conference on animal sentience next month which will examine the ability of a foetus and newborn to receive sensory information and to "feel" sensations that cause suffering.

His paper will argue that the embryo and foetus cannot suffer before or during birth, and that suffering can only occur in the newborn when the onset of breathing sufficiently oxygenates its tissues sufficiently.

He said many paediatricians were convinced that a foetus could feel pain because they based their judgment on comparable premature infants born as early as 24 weeks to 28 weeks.

Those infants did experience pain, and paediatricians had assumed that so did an age-equivalent foetus.

"But the chemical environment in the brain is very different after the baby is born," he said.

Breathing oxygen was a key difference, in addition to loss of the chemicals produced by the placenta.

When a baby was born, breathing oxygen caused a critical chemical messenger, adenosine, to be cleared from the bloodstream in seconds, allowing it to start experiencing consciousness.

This indicated that stillborn babies that did not breathe did not suffer pain or distress - they simply went from being asleep in the womb to profound unconsciousness and death.

Professor Mellor said future research would look at differences between foetuses of normal and caesarian births. Early indications were that, providing the foetus could breath sufficiently well to oxygenate its blood, the loss of placental adenosine, the stimulation of cold air, loss of buoyancy and "mechanical" touch would mean a baby from a caesarian birth would not be different to one which had gone through a normal delivery.

There was no doubt that babies before birth reacted to stimuli because the sense organs of foetuses in the uterus began to work well before birth.

"But the evidence, accumulated over the last 25-35 years, is that this does not occur at the conscious level."

Though effects from stimulation of touch, sight, sound and taste were not at a conscious level, "some evidence suggests that it is likely such effects persist well beyond birth.

"Some might well be benign, perhaps even positively advantageous, depending on what they are. Playing music and speaking softly could well have beneficial effects."

- NZPA