** EDITED 09.08.18 to add information on this study:
Das, R. K., Tamman, A., Nikolova, V., Freeman, T. P., Bisby, J. A., Lazzarino, A. I., & Kamboj, S. K. (2016). Nitrous oxide speeds the reduction of distressing intrusive memories in an experimental model of psychological trauma. Psychological medicine, 46(8), 1749-1759.
This study found that Nitrous oxide speeds the reduction of distressing intrusive memories in an experimental model of psychological trauma- but in dissociated individuals N2O aggravated PTSD-like symptomatology.
Considering that nitrous oxide (gas and air) is commonly used during labour it may be that this effects women birthing that have PTSD or the development of PTSD after a traumatic birth.
*This post evolved out of my birth experiences, attending over 40 births as a doula, and conversations with women and their partners at the home-birth group in Liverpool that I ran over a number of years. Quotes come from conversations on the #MatExp Facebook group. This is a long post, there is a summary of points made and implications for practice at the end
Transition to Motherhood
The transition to motherhood is a profound psychological event, which has been described as a ’normative crisis’ in the female life cycle requiring the giving up of one identity and the assimilation of another. This can be accompanied by changes in behaviour, mood and self that can feel overwhelming. There is little professional or public literature which agrees on the psychological symptoms women experience.
In antenatal classes women are prepared for childbirth and motherhood, mainly through factual accounts of the physical processes occurring, how the baby develops and grows, the changes in the body, how the cervix dilates, uterus contracts to push the baby out. Breasts produce milk for the baby. But there is little preparation for the mental changes that occur in pregnancy, birth and postnatally, except for warnings about low mood. Psychological changes are seen in the lens of deficit and crisis.
Adolescence too, whilst historically and culturally celebrated, in the western world is also increasingly seen as a ‘risky’ time and surveillance encouraged for potentially pathological symptoms. 
These transitory times of life which include psychological ‘crises’ include puberty, marriage, birth, and death, have been marked by initiation rituals since prehistoric times. Native and premodern societies used rituals during these transitional periods in life, (which are viewed as normal and expected personal development and growth) to celebrate and assign social identity.
The social meaning given up to Motherhood in Western modern society is that woman should be happy, content, enjoy mothering and that mothering comes naturally.  This comes in a social setting where there is increasing pressure on women to be financially independent, leading to later age to start a family, and fewer women experienced in childrearing of younger siblings. There has also been a movement away from organised religion.Thus the removal of childbearing experiences from the religious realm has created a culture with “no sacraments for the blessing of childbirth, no ritual to support a woman in childbirth”; this, in turn, “robs this part of feminine life of all its psychological depth and importance”
Three phases have been said to occur during all initiatory processes: separation, liminality, and integration. (For motherhood, this could be marked by pregnancy, birth and postnatal phases)and childbirth can be seen as similar to initiation ritual through several psychological elements, such as the experience of pain or powerful bodily sensations, an altered state of consciousness(’laborland’) a symbolic experience of death and rebirth, self-‐ transcendence, or an ecstatic feeling of unity.
Mental state during childbirth
Although little literature exists to describe to expectant women how being in labour feels, there are cultural expectations of women’s experience and behavior during birth, which usually revolve around pain and drama. Midwives describe using women’s behavior to assess whether active labour has begun and how labour is progressing.[10-12] this behavior is described as ‘labour-land ‘or being ‘In the zone’ and is thought to be due to the hormones released during labour and the pain of contractions.
“Hormones also have an effect on the way pain is experienced in labour. The hormone called beta-endorphin is an opiate or pain-killer that occurs naturally in the body. It is similar in a number of ways to the synthetically produced drugs pethidine and morphine. The subtle balance of hormones changes again when the cervix reaches full dilation. This phase is called the ‘transition”
“Labor land is like a deep meditative state. It is like an out of body experience except that it occurs so internally, totally within your body and in the meditative part of your mind. Being in this state allows the mom to get into the rhythm of her contractions and to develop a routine of what works for her to stay on top of the intensity of her labor.
It is important that no one tries to talk to her or pull her into her conscious mind when she is in labor land. This can take her out of her zone and make it more difficult for her to deal with the sensations she is experiencing.
Some people don’t appreciate the power and importance of labor land and interpret this altered state of consciousness from the outside as a state of weakness where the woman is incapable of dealing with what is around her. This is not a state of weakness but a state of great strength. This is where a woman accesses the full power she has within. Being able to go so internal does leave her vulnerable to outside stimulation. As a support person you are the protector of her space. Your job is to take care of all the external factors so she can stay internal through the birth.”
These changes of behavior in active labour include:
- Sense of separation of mind and body
- Altered time perception
- Zoning or spacing out
- Feeling like things are unreal
- Being unaware of things happening
Women and midwives have also described:
- Not wanting to eat or drink (altered taste perception)
- Altered sense of smell
- Sensitivity to noise and light
- Not wanting to speak, be touched, and communicate
These types of behaviour are known in psychology as ‘dissociation’ and describe a ‘detachment from reality’. This detachment can be temporary (linked to a particular experience) or on-going/repeating.
Dissociation is thought to be a normal human function and is a spectrum that encompasses daydreaming, meditation, hypnotherapy. Dissociation is used by athletes to cope with performing at the limit of their capabilities for long periods. . Lack of an ability to dissociate may be linked to anxiety disorders.
Dissociation is also the means by which the mind protects itself from trauma (and is associated with post-traumatic stress disorder-PTSD). When an experience is traumatic the mind dissociates, however sometimes (especially if the experience is repetitive in nature) or happens during childhood, the dissociation can reoccur in situations that are not currently traumatic or even lead to multiple identities developing.
Altered states of consciousness and dissociation during childbirth
There have been few studies that have looked at how common experiences of dissociation are during childbirth. Two recent studies found a prevalence of approximately 10% (11.3% of the sample experienced significant dissociation.) 
One of these studies found that important predictors of dissociation in labor included both predisposing (e.g. childhood maltreatment trauma, pre-existing psychopathology) and precipitating (e.g. perception of care, negative appraisal of labor) factors. 
Other studies have found much higher rates using qualitative methods (it may be the reports depend on factors such as when women were asked, what instrument is used to measure experience and cultural factors). In Anderson’s study on women’s experience of the second stage of labour sense of separation of mind and body was one of the strongest findings in her study the author concluded that disassociation was not a frightening experience but it enabled the women to keep in control. 
It may be that a woman’s interpretation of her experience as unexpected and/or different/abnormal may affect whether the experience of disassociation during childbirth is adaptive (useful/helpful) or maladaptive (frightening/trauma inducing).
Whilst in a dissociative state “Some sensory cues are likely to provoke alarm in us all, such as sudden unexpected loud noise or rough aggressive touch” (from http://www.iriss.org.uk/resources/trauma-sensitive-practice-children-care)
“At the heart of trauma is terror”
Another consideration is what occurs during disassociation (if the woman experiences interventions, upsetting care, coercion or difficulties during the birth).
A combination of negative emotions prior to and during birth (particularly shame) with dissociation and an instrumental delivery appear highly correlated with developing PTSD after birth. Both dissociation and shame can adversely affect interpersonal relationships (which may make it difficult for midwives and other care-givers to create and maintain a positive relationship with a woman during childbirth, and suggests that continuityof care may mitigate this by building up trust and respect prior to labour.)
This may also be why changes of shift can be difficult for women who have built up a positive relationship with a midwife as they can interpret their leaving as abandonment or feel unable to build a relationship with a new caregiver.
Transfer from one environment to another (MLU to CLU or home to hospital) can also be trauma inducing. 
The hospital environment itself can be triggering, as an unfamiliar environment may present as a threat (which is why making birth environments as home-like as possible is not just window dressing but may actively prevent trauma).
Place of birth appears to effect both optimism and resilience, with home and natural hospital births being associated with a better childbirth experience. 
The recent UK NHS maternity review suggested low-risk women should be encouraged to birth at home or in a midwife led unit. 
I asked women on the #MatExp Facebook group (over 1000 women, partners and healthcare providers interested in improving maternity care) about their experiences of disassociation during labour.
“My first labour I freaked… I hated everything about it, and if I could have exited my body there and then I would have. I felt “spaced” and drunk and I didn’t know what time it was. I can’t really describe it well – sorry. Second time round I listened to hypnosis during labour and it really grounded me, as a result I felt much more in control and towards the end I even announced I was bored!”
“I remember getting so annoyed at the midwives talking with my second. I had my headphones in and I could still hear them even though they were being respectful (and it turned out there was some pretty scary stuff happening with my baby) but I could hear them whispering and I wanted to tell them to shut up because I was concentrating, but I couldn’t find my voice. And when they touched my arm to get my attention I was SO angry with them for breaking my little bubble. Feelings I’d never have usually.”
“It was definitely like a trip. First time, 2nd was too quick and I was too in my rational head until the last 5mins. But first time I had that amazing experience of connection: to all the mothers who were labouring with me in that moment around the world, to all the mothers who ever had been and all the mothers who ever would be. It was enormous and wonderful and comforting. The daffodils out of the window meant something deep and meaningful too, but can’t for the life of me remember what! Anyway, definitely like one of those trips where you’re convinced you’ve got the answer to life, the universe and everything!”
“Like being in a parallel universe. Human interactions are difficult and confusing. Strangers are scary. I was unable to speak, unable to even access the vocabulary! All sensations on high alert and almost unbearable: slightest noise, smell, taste, light. Everything is very black and white like when you’re a child.”
“My first labour I had birth trauma. I felt like a bystander with everything happening to me but no involvement from me, a nightmare that ended up with a fully dressed baby that could have been anyone’s handed to me. I watched myself being cut open via the lights in theatre &it was like watching it happen to someone else on a YouTube video. My vbac’s were very different, I did still have an “out of body” experience when in active labour, I was very aware of touch & vocal about whether I liked it or not. I also hypnobirthed & felt more aware of what was happening in my own body, I knew my 3rd baby was on his way well before my midwife did & didn’t need a VE to tell me otherwise.”
“Being in an altered state is the only place to be in labour in my view. Enabled me to transcend some less than idea birth environments and supporters. Did not protect from ptsd in first (difficult) birth – I think because the sensations are kind of imprinted deep in the psyche when you are in that state. Even now I long to dance in the stars as I once did – and thank the Goddess for those amazing experiences.”
“Yes definitely an altered state, that wasn’t scary for me as it’s how I’ve always got through severe pain or fear and it feels like something I can control (lack of control – now that does scare me!) The down side was that I seem very quiet and calm and I don’t think anyone around me realised how bad the pain and exhaustion had got. I also found it impossible to maintain that and have a conversation and make decisions. Unfortunately as we hadn’t planned at all for things going wrong and I didn’t know the midwives there wasn’t really anyone I could hand over to.”
“This is how gas and air made me feel! Everything was spinning, I was detached, couldn’t form a sentence, it was awful..”
“Second time was definitely a trip! I had no drugs at all. At times I completely went inside my body and experienced the contractions as balls of intense creation energy, sorry if that sounds so hippie but there is no other way to describe it! I felt like a goddess! In between I felt stoned or slept. Amazing! Afterward I felt healed from my first (highly medical) birth.”
“I felt horribly out of it during my second labour. I remember telling my husband I needed the loo and he got a little cross, telling me I had to speak up and tell be midwives but I couldn’t. I was literally frozen with fear. At one point I had a senior midwife holding open my cervix with her hands, two anaesthetists, three other midwives and two doctors in the room with me, all wearing masks, all talking over me. I’ve always felt so guilty about not being able to speak up and blamed myself for a long time for what happened. I didn’t know it was a common thing for women to feel that way”
“I remember them discussing me getting an epidural as my blood pressure was so high and I was just on the bed screaming through the contractions. Everything was so fuzzy. I knew they were talking about doing something I didn’t want but couldn’t do anything about it. An anaesthetist kept coming in and out. In the end I was fully dilated before they could do it so I never had it. Terrifying.”
“I loved my first two stages of labour, didn’t feel it hurt at all, laboured unexpectedly quickly (from midwife who didn’t know me point of view -she later asked if I had a high pain threshold – I don’t remember it being painful at all until she pulled out the placenta) at home so when paramedics arrived I smiled and was happy to have them in my birthing space as only my husband was there who was an unwilling birth partner. They said they didn’t realise how far I was along as I was so calm. I remember them trying to hold my hand and I thinking I didn’t want them in my personal space. Also they tried to give me gas and air which I hadn’t asked for and being irritated I had to push it away, it was interfering in my space. Then after she came out I turned to pick her up and they shouted ‘no’ at me – it knocked me out of my zone and into fear and compliance – I feel traumatised about that. And I saw them get my baby’s first gaze, I was devastated!! She was cleaned before she was given to me and I transferred into hospital for placenta delivery after being told no midwifes available to come out to me. In retrospect I wish I’d free birthed or had a doula as everything was so lovely before anyone interfered.”
“Regards ‘altered state’ yes. I had a long induction (started in the Monday morning, baby delivered at 10am on the Thursday by forceps) where I was left alone a lot and really expected to know what was happening without anyone telling me. I felt very very isolated and detached. Wandering the corridors of the ward at night unable to sleep or eat. Labour was around 20 hours and not allowed to eat and couldn’t rest. Was put on a drip for fluids only during labour. I think lack of sleep and nourishment really contributed to my trauma. I was so spaced out. I’ve no doubt some of the midwives tried to communicate with me but I didn’t take anything in. In theatre I had a traumatic delivery. Baby was out very fast and then taken to NICU – I then had a 4.5l PPH during a further 2.5 hours of surgery to try to stop the bleeding under spinal block. I lost consciousness at one point – I really thought I had died. I really thought I could just let go. I felt like I was watching myself on the table at times. Covered in blood. The whole time I felt like I was going to fall off the table (strange angle to preserve blood flow to my head) so felt in constant danger the whole time.”
“I had gas and air at a few points too and that was mind altering in a different way, quite nice when I thought things were going well and I could chat away on it though I was a little concerned I was embarrassing myself like a drunk person! Once it was clear things weren’t going well I was given it again but it did nothing for the pain and I just got rather paranoid and scared, so I think state of mind before hand is quite important, with my third I experienced going inside my body and I actually saw my son going through the birth canal from Inside it was so weird but amazing and I had no drugs”
It seems there is a complex relationship between previous experiences, personality type, the natural process to dissociate during childbirth and experiences during childbirth (which encompass both intervention and care) which affect the sense of agency and body ownership and may or may not lead to PTSD after birth.
Pain, memory and PTSD
The relationship between pain, dissociation, childbirth and PTSD is not simple and the literature is contradictory. Studies have predominantly showed that women underestimate the pain they would experience during birth. 
Epidural anaesthesia has been associated with a lower prevalence of postpartum depression but not PTSD. Women have described feeling ambivalent about epidural pain relief. Describing relief but a change from euphoric to a ‘normal ‘state which indicated to the author that the internal experience is in focus before the use of epidural analgesia, while the more external experience is predominant after initiation of epidural analgesia. Optimal desired pain control during the birth process may decrease the prevalence of postpartum depression.  How we interpret pain has everything to do with how we will respond to it and our expectations and emotions also play a part in how we experience pain. Memory of pain and affect is influenced by the meaning and affective value of the pain experience. In a study where expectations and memory of pain were studied in women, who gave birth by vaginal delivery or Caesarean section, or underwent gynaecological surgery, surgery led to an overestimation of all but one of the recalled variables of pain. Participants who gave birth by Caesarean section were the most accurate at recalling pain and affect. Memories of pain and affect were most variable in participants who gave birth by vaginal delivery. 
Fear of childbirth results in experience of more intense labour pain and report a negative experience of birth. 
When studying women’s memory of labour pain post childbirth it was found that memory of labour pain declined during the observation period but not in women with a negative overall experience of childbirth. Women who had epidural analgesia reported higher pain scores at all time points, suggesting that these women remember ‘peak pain’.
Protective factors relating to PTSD and childbirth
A critical review of qualitative literature relating to the factors affecting women’s experiences of pain in labour found two main themes (i) the importance of individualised, continuous support and (ii) an acceptance of pain during childbirth 
In a second critical review of qualitative research this time looking at women’s experiences of coping with pain during childbirth feeling safe through the concept of continuous support was a key element of care to enhance the coping ability and avoid feelings of loneliness and fear. A positive outlook and acceptance of pain helped women cope. These findings were consistent across socio-economic, cultural and contextual differences suggesting that experiences of coping with pain during childbirth are universal. 
The ability to move during labour, and change position can be helpful both to facilitate birth without injury  and also a greater sense of control . In one study where women randomised to kneeling or sitting positions in the second stage of labour.A sitting position during the second stage of labour was associated with a higher level of delivery pain (P < 0.01), a more frequent perception of the second stage as being long (P= 0.002), less comfort for giving birth (P= 0.03) and more frequent feelings of vulnerability (P= 0.05) and exposure (P= 0.02). 
A study in Taiwan found women that were randomised to an upright pushing position had a lower pain index (5.67 versus 7.15, p=0.01), lower feelings of fatigue post birth (53.91 versus 69.39, p<0.001), a shorter duration of the second stage of labour (91.0 versus 145.97, p=0.02) and more positive labour experience .
An upright birthing position has also been shown to enhance fathers’ experience of having been positively and actively engaged in the birth process  which is important as men can also develop PTSD from childbirth [38-39], Women who report experiencing less stress in their couple relationship are less likely to report PPD symptoms even when they have a personal history of depression and or PPD  and a woman’s perceived social support has been found to buffer against the potentially traumatic effect of an emergency C-section.
Both mothers and fathers mental health after birth can effect parent-baby interaction and attachment. 
Having a high ‘sense of coherence’ was protective against PTSD following childbirth . The three constructs that underpin the SOC are ‘comprehensibility’ (one must believe that one understands the life challenge), ‘manageability’ (one has sufficient resources at one’s disposal) and ‘meaningfulness’ (one must want to cope with the life challenge).  A review of the literature found that women with strong SOC were more likely to experience uncomplicated birth and birth at home, identify normal birth as their preferred birth option in pregnancy and identify a desire to avoid epidural anaesthesia in labor compared to women with low SOC. 
Increasing pregnant women’s sense of coherence could be a modifiable factor to increase the normal birth rate, reduce PTSD and reduce improve postpartum emotional state. .
As previously discussed, pregnancy and motherhood can be seen as a ‘normative crisis’ and requires profound psychological role transition. Childbirth marks the separation of mother and child as a unit:
“The extreme nature of this experience is what makes the act of delivering a baby a psychological transition, an event of trial and ritual that marks a profound change in a mother’s life.”
There are similarities between mystical and traumatic experiences  and self-induced stress is used cross-culturally as a form of healing. 
“In rituals and with medicinal plants, people push past normal limits in order to experience power, energy, and transformation” 
Substances that that create dissociative states (like LSD, peyote, MDMA) have been used historically and culturally for ritual and healing and are also used recreationally in contemporary western contexts. Users describe the capacity of hallucinogenic drugs for healing and personal growth; even adverse experiences (“bad trips”) were regarded as valuable for these purposes  and some small studies have also looked at using hallucinogens to therapeutically treat long term PTSD and treatment resistant depression. [50-51]
Posttraumatic Growth (PTG) – deriving benefits following potentially traumatic events – has become a topic of increasing interest.
Some studies have looked at PTG after childbirth. Many women report positive changes as a result of their birth experience experience of peritraumatic dissociation and symptoms are most associated with the greatest levels of growth.  Posttraumatic growth in postpartum suggest a potential protective role of posttraumatic growth on the development of disordered eating symptoms. 
Social support has been seen to predict PTG. 
The transition to ‘motherland’ (constructing a new identity as a mother) can be hindered by traumatic birth experiences that reduce sense of coherence and the ability of the body to successfully birth or feed their baby. 
Mastering pain has been viewed as an integral part of a self-actualizing experience. Women have described a sense of achievement and feeling of pride in their ability to cope with intense pain, which increased their sense of self-efficacy. When empowered by their own attitudes and with the assistance of others, these women felt they met and mastered their birth experience, and some described giving birth as a transcendent experience. 
A study exploring first-time mothers’ experiences of birth found that women ‘processed the birth’ by ‘remembering’, ‘talking (storytelling)’ and ‘feeling’. This activity appeared to help most women resolve their feelings about the birth and understand what it actually means to be a new mother. 
I asked an antenatal teacher what they taught women and their partners about state of mind during birth:
“I talk about undisturbed birth producing sensations of an altered state of consciousness facilitated by the increase of the hormones Beta-endorphin and Oxytocin. I describe this as a natural, helpful aspect of undisturbed birth, producing feelings like being “in the zone,” “miles away” or “going off to another planet” combined with the body’s natural pain relief.
As a hypnotherapist I talk about these experiences as being a form of “birth hypnosis” / “birth trance” which can also include (positive) time distortion, altered physical sensations, and sometimes visual or auditory perceptions; all normal aspects of hypnosis. I introduce this state through a series of exercises and ask their partners to observe. We spend time on how partners can help facilitate and protect this helpful state for their partners. I teach them to practice entering this state with self hypnosis and recordings which I create for them in order to make it a welcome and familiar part of birth for the woman and her birth partner so that it is there to tap into during birth. This was certainly my own experience in my second (pain-free) birth where I used hypnotherapy and self hypnosis.
Unfortunately this state is inhibited when birth is disturbed, when a birthing woman is fearful and in the fight-flight-freeze state. I think first time birthing women often push this helpful aspect of birth away, feeling that they need to stay “on top” or “in control.” When high levels of Catecholamines: adrenalin and noradrenaline are produced, fear and pain (without the soothing effects of beta-endorphin) are part of birth. I suspect that this is where traumatic experiences arise. The combination of (negative) time distortion and possible visual and/ or auditory hallucinations with fear and pain is certainly frightening and I suspect for some women traumatising. This was the case for me in my first posterior birth.”
- The transition to motherhood is a profound psychological event, which has been described as a ’normative crisis’ in the female life cycle.
- Transitory times of life which include role changes (puberty, marriage, birth, and death) have been marked by initiation rituals since prehistoric times.
- Childbirth can be seen as similar to initiation ritual through several psychological elements, such as the experience of pain or powerful bodily sensations, an altered state of consciousness (’laborland’) and a symbolic experience of death and rebirth.
- Many cultures use substances to create dissociative states during rituals and for healing.
- Dissociative states of ‘altered consciousness’ are commonly experienced by women during childbirth.
- These states help women cope with the experience of childbirth and may prime women to experience the profound psychological shift to motherhood.
- If women are unprepared for this dissociative state they may feel frightened or ashamed, especially if women experience traumatic care or interventions, this can result in women developing PTSD.
- Fear of childbirth results in experience of more intense labour pain and report a negative experience of birth
- Women who have unmedicated vaginal births are more likely to forget the pain of labour. Having an epidural can make women feel disconnected from the labour process and more likely to remember their labour as painful.
- Two main factors effect women’s experience of pain in labour:
- Support and (ii) acceptance
- A positive outlook and acceptance of pain helps women cope, experiences of coping with pain during childbirth are universal
- Freedom to move and adopt upright positions in labour give women a greater sense of control and a lesser sense of vulnerability and facilitated a positive birth experience.
- Having a high ‘sense of coherence’ is protective against PTSD following childbirth
- Childbirth is “an event so primitive and profound as to be difficult to fully assimilate or put into words. . .”
- Even if birth is experience as traumatic, it is possible to women to experience posttraumatic Growth (deriving benefits following potentially traumatic events)
- Experience of peritraumatic dissociation and symptoms have been found to be most associated with the greatest levels of growth.
- Social support is a modifiable factor that effects coping with childbirth, PTSD, PPD and postpartum transition to motherhood
Implications for woman and midwives
- Antenatal education should prepares women for the possible psychological changes and experiences during pregnancy, birth and postpartum (including dissociation)
- Continuity of care is key to a feeling of safety and trust
- Preparation for childbirth should aim to reduce anxiety and enhance women’s sense of coherence and efficacy (including methods of non-pharmacological pain relief and mindfulness) [59-60]
- Maternal freedom of movement throughout labour is a simple measure to improve birth experiences for women and their partners
- Interventions to improve social support for women and enhance couple relationships in the antenatal period is key to improving postpartum mental health and improving parent/infant attachment
- Childbirth can be seen as a spiritually transforming experience, an increase in personal meaning, religiosity, and spirituality can increase well-being so access to the opportunity to incorporate personal spiritual practices or social experiences (such as mother blessings https://magicalbirth.wordpress.com/2012/05/03/hello-world/ ) could be helpful 
- Doula support can provide women and their families with continuity, one-to-one focus on their physical, emotional and spiritual needs during childbirth and postnatally to improve women’s self-efficacy and transition to motherhood and so could significantly affect women’s mental health in the peri-natal period and increase family sense of coherence
- Providing opportunities within a group for women to tell their birth stories following birth; may help women to process the birth and connect to other women.
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