Perth Birth Nerd

The Homebirth Series, Reason # 3

What is physiological birth?

A physiological birth is one in which the baby is born under the action of the woman’s own body alone, with the baby’s help, of course. This is a fascinating and complex process, which involves interplay between different hormones, the nervous system, movement in the woman’s body, and environmental factors that impact these. Science is still working to explain the initiation and flow of these processes, such is the intricacy of the systems. 

If physiological birth is allowed to unfold, then the baby will be born without assistance from external people, medicine or surgical tools. The same goes for the birth of the placenta too- after the baby arrives, the placenta is born, and this can also be physiological (although the default in hospitals is to actively manage this with medication).

What conditions promote physiological birth?

The best conditions for physiological birth are those that:

1. Promote the release of oxytocin from the pituitary gland, which acts on the uterus to cause effective contractions.
2. Increase the levels of melatonin, which improve the action of oxytocin on the uterus by up to one hundred times (Olcese & Beesley, 2014). 
3. Keep adrenaline low, until the very last part of labour, as adrenaline inhibits the release of oxytocin. 
4. Make the woman feel private, safe and unobserved (Buckley, 2018, which will allow oxytocin to be released while limiting adrenaline in labour. 
5. Allow the woman to be comfortable in labour, including being warm and having comfortable places to sit or lean. 
6. Allow the woman to move around and into many different positions, and remain in these positions comfortably. 

The Power of Oxytocin

Dr Sarah Buckley, makes this excellent (and, I think, rather humorous) comparison: 

“This may sound an odd thing to say, but from the perspective of your body (and the science of your hormones), the best environment to have your baby is the same environment where you could make a baby– or at least have a good time trying!.

In fact, the hormones of sex and birth are almost identical, and both activities require us to feel private, safe, and unobserved in order for our hormones to fully flow. We need to be able to turn down the alert, rational parts of our brain, and sink into our more primitive “limbic system,” which is where our mammalian birthing– and mating– hormones are made.”

(Gentle, Natural Birth for Modern Mammas, 2018). 

Movement Magic

Movement is also key in labour and birth. Moving allows the baby to move lower into the pelvis, and then to twist and exit. Certain positions help with this process, and in settings outside the hospital (i.e. at home or in birth centres), women tend to adopt a number of positions during labour, instinctively, to facilitate this. 

There is plenty of evidence to support the idea that adopting  multiple positions, particularly upright ones, improve outcomes for women. Kibuka et. al. 2021 found a reduction in length of time for first and second stage of labour, as well as a decrease in C-Sections and assisted vaginal births with forceps and vacuum, for women in upright and dynamic positions, compared to lying down positions. 

Priddis et. al. (2012) reviewed literature on this subject and also found that women who utilise upright positions during labour have a shorter duration of the first and second stage of labour, and experience less intervention. And further to that, they also found that women in upright positions report less severe pain and increased satisfaction with their childbirth experience than women in horizontal positions.

 From my personal experience, movement was the best pain relief I have used in labour, out of all the pharmaceutical and non-pharmaceutical methods I have tried. It was also so useful for moving my girl down through my pelvis in that last hour or so, I could literally feel how my movement was affecting hers (gosh, birth is just wild!). 

Maternity Wards are not Built for Birth

Whilst rooms in most maternity wards are built with excellent features to deal with emergencies, they are not designed with what science knows about physiological birth.

For example, they have bright, fluorescent lighting. While these can be turned off in the room, they permeate from the hallways, and most bathrooms have automated lighting, so a birthing woman cannot even shower in semi-darkness. This inhibits melatonin, which suppresses effective contractions (Olcese & Beesley, 2014). 

Most rooms lack soft furnishings such as rugs, or couches which can make the woman (and her team) feel comfortable. There is the hospital bed, but this tends to be more a tether than comfort. The smell, sounds and sights in hospitals can be stressors on many women’s nervous systems, increasing adrenaline and further slowing the progress of their labour. 

And it’s not just the buildings, it’s the policies and procedures too. 

Policies that Hinder Birth

Many hospital policies work against the flow of physiological labour. 

For example, almost every woman is “offered” a cervical check, or vaginal exam (VE), when arriving at hospital (for information about why this is not an evidence-based approach to care, see the next article). VE’s are uncomfortable, at best, and can sometimes be quite painful, particularly as women are required to lie on their backs, which can be extremely awkward during labour. This intervention can move a woman from being “in the zone”, or in her limbic system, feeling safe and unobserved, to a state of hyperawareness and adrenaline. This interruption to physiology can be quite difficult to recover from, especially coupled with the change of environment, lighting and so on. Hospital policies usually require routine VEs every two to four hours, which continue to interrupt the hormone loops and labour. 

CTG (Cardiotocograph) monitoring is an intervention that is being used on a growing number of women during birth, without evidence to support its use (read more here). Unfortunately, the CTG tethers women down, usually to the bed, and prevents the movement required to facilitate birth. This, in itself, can slow down labour and leads to an increased number of instrumental births and caesarean sections. (Alfirevic et al, 2017). 

Other policies in hospitals are likely to activate women’s adrenaline production or fight or fight response. This includes having multiple, unfamiliar staff rotating through during labour and birth, which deprives women of feelings of safety, privacy and being unobserved- the cornerstones of physiology. 

Going back to Dr. Buckley, it might be useful to ask yourself this: Could you and your partner achieve orgasm on a hospital bed, in a hospital room, with the machine that goes “beep” in the background, under fluorescent lights, while strangers walked in every so often to make sure it was progressing as “normal”? 

There’s no place like home

Whilst there is much women can do to enhance their chances of physiological birth in a hospital, such as wearing an eye mask, or having doula as part of their birth team, the simple fact is that the medical environment is working against them. This is a reason that women are routinely told to stay at home for as long as possible before going into the labour ward. 

At home, on the other hand, we have the perfect conditions for making babies, and therefore the perfect conditions for having babies. Home is safe and private, and only those you invite into your space will be there. Our homes are far more comfortable than hospital rooms, and we can control the lighting, the temperature and the sounds around us. Homebirth midwives, by their very nature, are passionate about promoting physiological birth- their livelihoods depend on it! They, therefore, tend to encourage optimal conditions, shying away from routine vaginal exams and monitoring with unobtrusive dopplers. 

Home is where the heart is, and it is the perfect place to start your next chapter. 

See References

Keep Reading: Reason #4 Hospital Policies are not always Evidence-Based, and are Frequently Short-Sighted

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