French obstetrician Michel Odent puts forward the very interesting question of what the basic needs are of labouring women. In order to answer this question he looks to physiological concepts such as adrenaline-oxytocin antagonism and the concept of neocortical inhibition.
The mechanism of adrenaline-oxytocin antagonism means that mammals (including humans) cannot release oxytocin at the same time as they release hormones of the adrenaline family.
Avoiding anxiety, stress and fear
Adrenaline hormones are implicated mostly in the fight or flight response. Since the release of oxytocin is what drives uterine contractions, labour either fails to come on or slows down when a woman is in an environment that evokes the release of adrenaline. The evolutionary advantage of such a system is obvious. While animals (including humans) are in labour and giving birth, they and their baby are at their most vulnerable. It makes sense that a physiological mechanism is in place to prevent labour and childbirth when a woman is in a dangerous environment. Feeling unsafe and the subsequent hormonal release are not under control of conscious thought. We cannot logically convince ourselves that we are in a safe environment because we are in the hospital and doctors will take care of us. One grumpy or tired midwife or being left alone without knowing in advance for how long is all it might take to trigger anxiety and a release of adrenaline. A research study showed that women who reported higher anxiety levels during labour had weaker contractions when they were three centimetres dilated and experienced a longer second stage of labour.
Hormones of the adrenaline family are not only released when we feel anxious or stressed, but also when we feel cold, observed or monitored, and even when we exercise. This has important implications for optimising the labouring and birthing environment.
The right temperature
In my experience it is usually cosy warm in hospitals. I assumed that this was entirely for the benefit of patients having to undress for examinations, but it seems to be advantageous for labouring women as well. When we feel cold, adrenaline starts flowing and oxytocin release is impeded. It’s not a bad thing to be prepared and bring some nice woolly or fleece socks to the hospital and a dressing gown to make sure that you stay warm at all times. This is also valid for the time right after birth. The expulsion of the placenta as well as the milk ejection reflex all depend on oxytocin, so it is very important to keep warm once you’ve given birth.
Privacy and feeling unobserved
The need for privacy that many women feel when in labour can be explained by the fact that adrenaline starts flowing (and oxytocin release is reduced) when we feel observed. It might be for this reason that observations of non-human primates (especially of the great apes) giving birth in the wild are extremely rare. This mechanism might also help explain why women who labour at home have shorter labours than women who labour in the hospital. In the hospital you can expect to be interrupted at any moment and by any number of caregivers who you may have never met before. It is the absolute opposite of privacy. In addition, you might be sharing a room with someone else and experience double the amount of interruptions and you might even receive a visit from the cleaning staff. In terms of observation, there are internal exams, monitoring of heartbeat and contractions, and a myriad of questions, suggestions and choices to make. And if that wasn’t enough, you have to adhere to certain rules: you are often not allowed to eat or drink, and you are mostly confined to your room, which is often not a cosy well-decorated room, but a cold clinical room where it’s hard to truly relax.
Rest and avoiding exercise
That exercise might be a bad idea during labour seems surprising. Modern labour suggestions include being upright, walking around, changing positions often and rocking back and forth on a Swiss ball. In addition many advocate keeping (or getting) in shape prior to childbirth.
For Louis I didn’t do any exercise during pregnancy or labour. Leonard was very worried about this because he was convinced that I needed to strengthen my muscles and increase my physical endurance so that I would be in good physical condition to handle labour and give birth. I have to admit that I didn’t take this very seriously and just did what I felt like doing during my pregnancy. Since I felt so sick, the absolute last thing I wanted to do was exercise. By the end of my pregnancy, I didn’t even walk much anymore, for the simple reason that I was suffering from round ligament pain and I needed to use the toilet every ten minutes. During labour I just went about my business as usual: I showered, got dressed, made lunch, ate lunch, sat around and leaned on a table when contractions started being more painful. Then I sat in the car for thirty minutes, walked from the car to the birth centre and got on the bed on all fours because that was the least painful position to be in. I gave birth thirty minutes later while lying on my side.
When I was pregnant with Lars, Leonard didn’t mention exercise at all. After contrasting my easy delivery with long labours and difficult births of several friends who had been exercising during pregnancy, he concluded that either it was better not to exercise or I simply didn’t need it. Labour came on at midnight. Since I wasn’t sure that this was the real thing, I went to sleep. I remember thinking that I really couldn’t be bothered giving birth now since I had been up all day and felt exhausted. I was hoping that the contractions would stop and I could get a good night’s sleep. I did manage to fall asleep (repeatedly), but was woken up by contractions every 15 minutes. After an hour I finally admitted that I must be in labour, woke up Leonard and got ready to go the hospital. There I gave birth nearly immediately while lying on my back. So I have to admit that the no-exercise idea worked pretty well for me. If anyone would have suggested to me that I start walking around while I was in labour, I’m sure that I would have completely ignored that person. In daily life I am a moderately stubborn woman, but during labour I became almost completely self-absorbed and just did what felt right to me. At the very end my thoughts were not logical anymore, but instead seemed very primitive and instinctual. I was very aware of my own body and what was happening to me, but somewhat oblivious to what was happening around me. I didn’t worry about making weird noises in front of other people. I simply did what felt right. And this brings me to the concept of neocortical inhibition and the foetus ejection reflex.
Neocortical inhibition and foetus ejection reflex
In mammals, giving birth may be considered an involuntary physiological process that is under the control of archaic brain structures responsible for the release of a specific hormonal flow. The term foetus ejection reflex was first coined by Niles Newton in the 1960s when she was studying the environmental factors that can disturb the birth process in mice. Michel Odent discovered that in circumstances that are exceptionally rare after thousands of years of culturally controlled childbirth, an authentic foetus ejection reflex is also possible among humans. It takes place when a baby is born after a short series of irresistible contractions, which leave no room for voluntary movements. Although the large majority of women must work hard during the second stage of labour and find it hard to imagine that a baby can be born without actively pushing, many home birth stories seem to agree.
For Louis I spent half an hour pushing him out, but with Lars it was a very different story. One moment I was walking to the hospital with labour pains that were painful but still quite bearable and ten minutes later I gave birth without one voluntary push.
So why is this foetus ejection reflex so rare among humans that many people don’t even believe that it exists? The answer lies in the difference between our brain and that of other mammals and even primates. The brain of a mammal consists of three different parts: reptilian brain, limbic brain and neocortex. The reptilian brain is responsible for aggression, dominance, and fight or flight behaviours, and the limbic brain deals with the motivation and emotions involved in nurturing and social behaviours. The neocortex is the newest part of the brain that handles higher cognition. It is biggest in primates, and of all primates, most powerful and developed in humans. The neocortex is responsible for our capabilities regarding language, abstraction, planning, and perception. Sadly, the activity of our powerful new brain can inhibit and interfere with the involuntary processes of the older parts of the brain during labour and birth. When our neocortex is at rest, we have more similarities with other mammals and birth is comparatively easier. In order to provide the optimal circumstances to give birth, we must not only avoid situations that provoke the release of adrenaline, but we must also avoid stimulants of the neocortex. Perception of danger and feeling observed, as well as rational language and bright lights, all stimulate neocortical activity.
Avoiding rational language and bright lights
It is very hard to imagine a birthing environment where talking is kept to a minimum. In a hospital or sometimes even in a birth centre setting we are constantly monitored, asked questions and told how far our labour has progressed. All of this stimulates the neocortex. Hearing about cervical dilation in terms of centimetres is thought to provoke more neocortical activity than just being told that things are progressing well (or not). In addition, many birth attendants (even among natural birth promoters) are coaching the labouring woman and giving suggestions on what to do, how to breathe and what position to try. All in all it’s a very active environment, making it very difficult to relax and surrender oneself to one’s instinctive feelings and needs. Michel Odent compares the physiological process (and its possible neocortical inhibition) of giving birth to another physiological process: the one of making love and reaching orgasm. He writes: “Imagine a couple in a pre-orgasmic state. Suddenly the woman asks her partner: ‘What do you want for dinner?’. Through neocortical stimulation, this simple question can interfere with physiological processes.” With other words: this question can delay or even ruin the chances of having an orgasm. I would go even further in my comparison. Imagine trying to achieve orgasm as your heartbeat or other body function is being monitored. Or imagine being coached to breathe or try different positions. And if you are a man, imagine someone (or even yourself or your partner) measuring the length of your erection to see how close you are to orgasm. Your orgasm would have to be pretty unstoppable to survive such observations and neocortical interruptions.
During lovemaking we find it obvious that certain basic needs must be fulfilled in order to reach orgasm: privacy, feeling unobserved, warmth, lack of logical thought and feeling safe enough to surrender to a more primal state of mind, one in which we can utter primitive sounds that would otherwise be unacceptable in civilised society. Likewise it’s no coincidence that many people also like to dim the lights to enhance the mood and facilitate orgasm. So why do we find these interruptions and observations normal during labour and childbirth, another physiological process that completely depends on the natural flow of hormones?
Leonard’s perspective on adrenaline-oxytocin antagonism
“Adrenaline-oxytocin antagonism”, what a concept! Maybe there are a lot of these antagonisms at work? I wonder if there’s a testosterone-shopping hormone antagonism that makes it impossible to simultaneously be a man and to go shopping? This opens up new possibilities: “Honey, I’d love to go shopping with you but I actually physically cannot. It’s this darn testosterone-shopping antagonism thingy that just prevents me from doing it. But I’m sorry, really. I would if I could.”
Click here to read more excerpts of:
Making informed decisions on childbirth
One scientist’s international perspective
by Sofie Vantiers, Ph.D.
- Odent, M., Childbirth and the Evolution of Homo Sapiens. 2nd revised edition ed. 2014: Pinter & Martin Ltd. 160.
- Lederman, R.P., et al., The relationship of maternal anxiety, plasma catecholamines, and plasma cortisol to progress in labor. Am J Obstet Gynecol, 1978. 132(5): p. 495-500.
- Douglas, P., Female sociality during the daytime birth of a wild bonobo at Luikotale, Democratic Republic of the Congo. Primates. 55(4): p. 533-542.
- Newton, N., D. Foshee, and M. Newton, Experimental inhibition of labor through environmental disturbance. Obstet Gynecol, 1966. 27(3): p. 371-7.
- Odent, M., “The instincts of motherhood: bringing joy back into newborn care”. Early Hum Dev, 2009. 85(11): p. 697-700.