Oxytocin and Adrenaline - nature's Yin and Yang
Not many people have heard of Oxytocin. And yet it is probably the most important hormone pregnant women, and their birth companions, should know about.
Oxytocin is the hormone that makes the uterus contract during labour to thin out and dilate the cervix, and to push the baby down and out. It is released after labour and birth to contract the uterus to stop excessive bleeding. It is released during a let down when breastfeeding. And it is released during an orgasm. It is what makes us fall in love and gives us that warm fuzzy feeling - not just with our babies but with other people. Michel Odent calls it the 'hormone of love'.
Adrenaline is the 'enemy' of Oxytocin.
Most people know about Adrenaline. Adrenaline is released when we feel fear, when we feel like our lives might be in danger. It causes blood vessels to dilate in essential organs, and restrict in non-essential organs. This increases oxygen to those essential organs and decreases oxygen to non-essential organs.
Essential organs are the heart, the lungs, the adrenals, and the muscles of the legs. These organs are necessary to either fight the danger or flea from it.
The uterus is NOT an essential organ.
If a woman feels threatened (whether she consciously knows it or not) her body will release adrenaline. This is actually a great design of Mother Nature - back when we lived in the wild, if a predator came sniffing around during labour it was probably not a great idea to give birth to a tiny, defenseless baby covered in blood. Adrenaline re-directs blood flow away from the uterus and can stop labour all together. This would give the women a chance to either flea from the predator or wait for it to leave.
But before it stops labour it can make it more painful - when a muscle contracts, it losses oxygen for a short time, and this can cause pain (think of getting a cramp). If blood flow is then being shunted away because of adrenaline then this will decrease the oxygen flow even more. The pain can make a woman tense up, which in turn makes it hard for the cervix to thin and open up - causing more pain, and so the 'pain-tension-fear' cycle begins (this cycle is described in Grantly Dick-Read's book 'Birth Without Fear').
By this same process oxygen to the baby can also be decreased, causing 'fetal distress'.
'Slow progress', 'failure to progress', 'fetal distress', and 'maternal distress/exhaustion' can all lead to medical intervention during labour and birth - epidurals, use of synthetic oxytocin to induce or speed up labour, caesarean sections, and instrumental births. All of these have their own risks and potential long term effects.
But if women feels calm, relaxed, and safe during labour, Adrenaline is not needed*. If labour is allowed to start and continue naturally (in the absence of true medical necessity for intervention), labour will usually progress as the women's body and baby needs it too. If Oxytocin is allowed to flow freely, the woman feels loved and in love. Some women even experience an orgasm during labour, which strengthens the effect of the Oxytocin. Labour may not be completely pain-free, but the level of pain or discomfort will hopefully be bearable.
*Adrenaline is released in small amounts during a natural labour. It gives women a boost of energy which is often needed, especially towards the end. This can be why labour often 'stalls' just before a woman gets the urge to push. But this can be a good thing - a chance for the woman and baby to have a much needed rest before the push towards the home straight (pun intended!). It is also often why many women beg for an epidural or medical professionals start talking about 'speeding' things up. Sometimes all that is needed is patience and a heavy dose of reassurance.