Background
Although childbirth is usually considered a positive life event, it is now recognised that labour and delivery have the potential to fulfil the traumatic stressor criteria as defined in the Diagnostic and Statistical Manual (fifth edition; DSM 5 [
1]). It is suggested that between 20 and 30% of women experience childbirth as traumatic [
2‐
4]. Approximately 10% of women may have a severe traumatic stress response in the initial postpartum weeks, but only between 0.8 and 6.9% of women will go on to develop posttraumatic stress disorder (PTSD) as a direct result of childbirth events [
2].
Not only is postnatal PTSD highly distressing for the mother, it can also impact negatively on her attachment with her child [
5,
6] and her relationship with her partner [
7,
8]. Furthermore, the presence of PTSD during a subsequent pregnancy can have an impact on birth weight and gestational age of the infant [
9,
10].
A range of perinatal risk factors that may increase women’s vulnerability to developing PTSD symptoms following childbirth has been established [
2,
11‐
14].
Pretraumatic risk factors include fear of childbirth which could include both a primary tokophobia presentation (fear of childbirth in women who have not previously delivered) or a secondary tokophobia presentation (fear of childbirth in women who have experienced a previous, traumatic delivery; e.g., [
15]), psychiatric history (especially previous PTSD), psychiatric difficulties during pregnancy and previous trauma (including previous traumatic childbirth or sexual abuse; [
2,
11]. Factors such as parity, socioeconomic status, age, ethnicity and unplanned pregnancy have shown associations with PTSD symptoms, although their influence can be small and inconsistent [
11].
Intrapartum risk factors thought to be especially important are subjective distress in labour (including pain, fear, dissociation during birth, but especially loss of control and negative emotions about childbirth) and obstetric factors such as emergency caesarean sections and instrumental deliveries [
11,
16]. Waldenstrom et al. [
17] highlight the particular impact of unexpected complications during the labour/delivery experience as having a significant impact. Severe infant complications and low support during childbirth are also associated with PTSD [
11]. For example, Pierrehumbert et al. [
18] examined the specific infant complication of premature delivery, drawing a clear link with impact on parental PTSD.
Postnatal factors that predict the development of PTSD have been less well studied. However, coping style, additional stress and in particular low social support appear to be associated with PTSD [
2]. For example, a lack of partner support has been identified as a risk factor for the development of PTSD following childbirth [
7] and good social support has been found to be protective against the development of PTSD following trauma in other populations (e.g., [
19]). Postnatal factors may be of particular clinical importance, as they may be the most amenable to change in order to prevent the development or maintenance of PTSD.
Although research into PTSD following childbirth is increasing and risk factors are becoming clearer, the literature lacks a strong theoretical basis [
20] and there is limited understanding of the postnatal factors that may help to maintain traumatic stress responses. The cognitive model proposed by Ehlers and Clark [
21] is widely used in the formulation and treatment of PTSD in other adult populations. It suggests that a sense of current threat is produced by negative cognitive appraisals both during and after the traumatic event. This threat, in conjunction with a fragmented and poorly integrated traumatic memory, can be unintentionally triggered by situations resembling some aspect of the traumatic event. PTSD is then maintained through unhelpful cognitive (e.g. thought suppression) and behavioural (e.g. reminder avoidance) strategies. Despite these strategies being aimed at controlling the sense of threat/symptoms, they can directly produce symptoms and/or prevent change in negative appraisals or the nature of the trauma memory. All components of the model have received empirical support in the general PTSD literature (for a review, see [
22]).
Evidence supports the utility of the cognitive model in understanding and treating PTSD in adults, but the qualitative difference between childbirth and what we traditionally consider to be a traumatic experience needs to be considered when evaluating its applicability to this population. Culturally, childbirth and motherhood are associated with positive expectations [
23]. Women can perceive the birth of their baby as a positive outcome even if the birth is appraised as traumatic [
24]. Women may have hopes and expectations for the process of childbirth that contrast with their actual experience [
25]. There are at least two individuals involved in any childbirth experience (mother and child) and the woman might fear for her own life and/or that of her (unborn) baby [
26]. Following a traumatic birth the mother is expected to form a close relationship with her baby, even though the baby may be a reminder of the traumatic experience [
26]. Ayers et al. [
27] found that for mothers developing PTSD following a traumatic childbirth experience, the mother-baby bond was significantly affected, and that in the longer term many of these infants appeared to be insecurely attached, highlighting the importance of this issue. Additionally, memory processes may be impacted by the use of systemic analgesic medication [
28]. It is therefore important to investigate if the cognitive model also applies to the childbirth population.
Previous studies have investigated single cognitive variables in isolation, such as memory disorganisation [
28], negative cognitive appraisals of the birth and its sequelae [
29] and perinatal dissociation [
3]. Two studies have more systematically examined cognitive predictors in a childbirth population. Ford and colleagues [
29] found that prior experiences, beliefs, and coping state as well as negative appraisals of childbirth explained 23% of variance in posttraumatic stress symptoms at 3 weeks post-birth. Vossbeck-Elsebusch et al. [
30] reported that peritraumatic dissociation, negative appraisals, thought suppression, rumination, and perseverative thinking accounted for an additional 23% of variance of PTSD symptoms after accounting for known risk factors. However, no study has so far looked at all the key processes described in the cognitive model. More comprehensive investigation of the cognitive model, including elements such as the nature of the trauma memory, peritraumatic processing (peritraumatic dissociation, perceptual processing, lack of self-referent processing), negative appraisals of trauma and/or its sequalae, and the use of dysfunctional cognitive and behavioural strategies (thought suppression, rumination, and numbing) may further our understanding of the applicability of the cognitive model in the development and maintenance of PTSD following traumatic childbirth.
This study therefore aimed to investigate whether theoretically-derived variables of the cognitive model explain unique variance in postnatal PTSD symptoms when key demographic, obstetric and clinical risk factors are controlled for. It was hypothesised that (1) Demographic, obstetric and clinical risk factors will explain some variance in PTSD symptoms; (2) Cognitive and behavioural factors derived from the Ehlers and Clark model [
21] will explain some variance in PTSD symptoms; and (3) Cognitive and behavioural factors will explain additional unique variance in PTSD symptoms when clinical, obstetric and demographic risk factors are controlled for.
Discussion
This study investigated whether theoretically-derived variables of the cognitive model of PTSD explain unique variance in PTSD symptoms in women following childbirth when key demographic, obstetric and clinical risk factors were controlled for. It was hypothesised that (1) Demographic, obstetric and clinical risk factors will explain some variance in PTSD symptoms; (2) Cognitive and behavioural factors will explain some variance in PTSD symptoms; and (3) Cognitive and behavioural factors will explain additional unique variance in PTSD symptoms when clinical, obstetric and demographic risk factors are controlled for.
Results indicated that when demographic, obstetric and clinical risk factors were considered alone, 43% of variance in PTSD symptoms was explained. Cognitive behavioural predictors alone explained 72.7% of the variance. When cognitive behavioural factors were added into a hierarchical regression with risk factors controlled for, the overall model explained 73.7% of variance, with cognitive behavioural factors explaining 37.1% unique variance in PTSD symptoms. The effect sizes are higher than those estimated in two previous studies [
29,
30] investigating only some aspects of the cognitive model in a childbirth population, thus confirming the usefulness of a comprehensive investigation of all key cognitive behavioural components of the cognitive model of PTSD.
We found that 5.7% of the sample met full DSM-IV criteria for PTSD. Although investigation of prevalence was not a key aim for this study as endorsement of PTSD symptoms has been found to be elevated in online samples [
43], this estimate is at the higher end of the range suggested by Ayers [
2]. Twenty-six percent of the sample fulfilled criterion A suggesting they experienced their childbirth as traumatic, which is consistent with previous findings [
29].
Regarding demographic, obstetric and clinical risk factors of PTSD, low levels of perceived safety during birth, low levels of partner support during birth, and the use of instruments to assist vaginal delivery emerged as significant individual risk factors. This replicates previous findings [
2,
11,
12]. Two of these remained in the final model of the hierarchical regression: low levels of perceived safety and instrumental delivery. Two new demographic, obstetric and clinical predictors emerged in the final regression: being single and low levels of perceived postnatal social support. However, neither instrumental delivery nor being single was significant in the final model once cognitive behavioural variables were included.
The finding that perceived safety during birth was the strongest significant predictor of PTSD symptom frequency (and remained in the final regression model) is perhaps unsurprising. It is consistent with the literature that identifies mothers’ subjective distress during childbirth and labour as one of the strongest predictors of PTSD [
11]. A low level of perceived safety would also be consistent with criterion A of the PTSD diagnostic criteria [
31] in that those who experienced fear, anguish, horror or helplessness during childbirth might reasonably be expected to also experience low levels of perceived safety.
The finding that partner support during the birth was a significant predictor is consistent with the existing literature [
26,
44], although many studies so far have primarily focused on professional support during birth [
45].
Previous reviews have identified obstetric emergency and mode of delivery as strong predictors of PTSD symptoms [
2,
11], although this finding has not always been consistent [
29,
46]. In the current sample, instrumental delivery was a significant predictor, which has previously been found [
47]. The current sample did not include mothers whose babies were cared for in special care baby units or neonatal intensive care unit for longer than four hours. It may be that the failure to find other significant obstetric factors (or indeed infant complications) is due to the inclusion criteria.
The final regression model identified positive postnatal social support as a significant predictor. Other studies have highlighted the importance of social support in predicting PTSD following childbirth [
29,
48,
49]. However, our model suggests that it is
positive social interaction following childbirth that is particularly protective. Alternatively, it is possible that women with higher levels of PTSD symptoms perceive less positive social interaction rather than objectively experience it.
Focusing on cognitive behavioural variables in our study, negative cognitions about the self in relation to the birth were the strongest of the cognitive behavioural predictors in both the original regression and hierarchical regression. These findings confirm that the addition of negative cognitions as a criterion for PTSD in the DSM-5 [
1] is appropriate and applicable to the postnatal population.
Regarding dysfunctional cognitive and behavioural strategies, thought suppression, rumination and numbing were significant predictors in the first regression, whilst rumination and numbing subscales remained significant in the final regression. Response to intrusions is thought to be a key posttraumatic variable in the maintenance of PTSD [
21]. Theoretically and in practice, there is some overlap between the numbing subscale of the RIQ and the avoidance and numbing symptoms of the TEQ. However, although correlations between the subscales were significant they were low (
r
s
= .18). This may indicate that the RIQ numbing subscale identified responses that may not necessarily be indicative of PTSD symptoms. This is consistent with hypotheses put forward by Ayers and colleagues [
43] who suggested that some predictors may be inflated by normal postnatal factors.
Deficits in intentional recall of the trauma memory were a significant predictor of PTSD symptom frequency. This is consistent with others [
28] who found an association between memory disorganisation and PTSD symptoms. Many factors within childbirth may contribute to difficulties in memory that do not necessarily relate to finding the experience traumatic, such as pain and medications used to control pain [
28]. However, results do suggest that intentional recall deficits are predictive of PTSD symptoms despite potential involvement of additional factors in the memory process. Surprisingly, low endorsement of negative appraisals of deficits in trauma memory was a predictor of increased PTSD symptom frequency. This finding is inconsistent with the positive correlation found with the variable in the sample and is not what would be expected. This result should be interpreted with caution, as the subscale only consisted of 3 items and was heavily skewed towards zero. It does suggest, however, that the impact of negative appraisals of recall deficits on PTSD symptoms is dependent on other variables included in the model, most likely intentional recall with which it is the most highly correlated.
Our study has some limitations, most notably the questionable representativeness of the sample recruited through the internet. The sample was entirely self-selecting and it is likely that those with an interest in research, reflecting on the experience of childbirth, or their mental health, were more likely to complete the survey. As such, any symptoms may have been inflated. It is not possible to know the nationality of the mother, although ethnicity was collected. This may have some implications in terms of the different health systems and cultural expectations about childbirth and mental health in different nationalities. In addition, we did not ask whether participants are first-time mothers or already have children, which might be a potential confounding variable. Secondly, the cross-sectional, retrospective design means that self-report of antenatal and birth-related variables may have been biased by the subsequent birth and postnatal experience or by current PTSD symptoms. This did not allow us to consider the role of the amount of time that had passed since childbirth, which is likely to influence some of the cognitive variables measured. Additionally, it is possible that the importance of post-trauma variables such as response to intrusions, cognitions and social support in the regression may be due to current symptoms being more sensitively measured than peritraumatic variables, largely due to the time that had elapsed since birth. Indeed, it has been reported that women’s memory of pain and birth experience can vary substantially between 2 months and a year [
50]. It is possible that the self-report measures used for both risk factors and cognitive factors have a greater chance of association with PTSD symptoms due to shared method error variance. Additionally, it is possible that the scales measuring cognitive and behavioural factors are more likely to relate to measures of PTSD than objective antenatal risk factors, as they inherently describe similar, internal phenomena. Finally, the sole reliance on self-report questionnaires is another limitation, which might have led to the overreporting of symptoms.
The strengths of our study are a well-powered sample and the inclusion of different risk factors within one regression model. We comprehensively tested the validity of the most established theoretical model of PTSD in a postnatal population, including negative cognitive appraisals, dysfunctional cognitive and behavioural strategies, and trauma memory, all of which could potentially be targeted in the prevention or treatment of PTSD.
Our study has important clinical implications. Although demographic, obstetric and clinical risk factors are important, the predictive strength of cognitive behavioural variables when controlling for known risk factors suggests that the cognitive behavioural model provides significant additional value in furthering our understanding of PTSD symptoms following childbirth. The strength of the predictive value of negative cognitions about the self is of particular clinical importance; feelings of shame, self-blame, guilt and responsibility are therefore likely to be most valuable to identify and for which to provide a specific clinical intervention. Childbirth is a common event and is rarely experienced as traumatic; therefore it is important to be able to identify those women most at risk. Cognitive behavioural factors may also be more amenable to change postnatally than many of the risk factors previously identified in the literature [
21].
The cognitive behavioural predictors that were identified as most significant are likely to be used already to inform clinical interventions for women experiencing PTSD following childbirth [
24], although to date, only one intervention study offering CBT to mothers following premature birth has been published [
51]. Our results confirm that the elements in the cognitive model are relevant to PTSD following childbirth and that CBT is likely to be clinically useful in this population. It may be that trauma-focused CBT interventions that support women to reduce negative cognitions of the self in relation to the childbirth, provide alternative responses to intrusions. In addition, work on deficits in intentional recall could be helpful. Furthermore, interventions based on CBT principles could also be built into postnatal groups for those most at risk, whilst also providing additional social support.
In terms of intra-partum clinical considerations, women’s perceived safety during childbirth appears important for the prediction of PTSD. It may be possible for medical staff to increase perceived safety in such situations, even if medical procedures are unavoidable. Additional qualitative research on the meaning of safety for women during childbirth may be beneficial in developing this finding further. Recent findings suggest that increasing psychological mindedness of the maternity service can in itself make a difference in terms of reducing trauma [
52,
53]. Midwifery staff was provided with specific perinatal mental health training, and a communication system was introduced into the maternity services between psychology and midwifery. While preliminary, results suggested a significant decrease in the onset of PTSD symptoms following birth within this system.
Low positive social interaction and partner support during birth were significant predictors of PTSD symptoms. It is likely that increasing postnatal positive social interaction for those women at risk (e.g. through signposting to relevant groups or creating a buddy system) or a focus on how partners can best support women during birth (e.g. during birth preparation classes) could help to prevent the development of PTSD. Positive social interaction was also strongly correlated with other types of postnatal social support. Therefore, increasing these types of support is also likely to be beneficial for those at risk of developing PTSD. These findings should first be investigated prospectively to rule out the alternative interpretation that PTSD symptoms impacts on the perception of low support, rather than low support impacting on the development and maintenance of PTSD symptoms. However, if it is the appraisals of support that are associated with PTSD, then cognitive behavioural therapy may be a beneficial intervention.
Future research might usefully focus on prospective designs to identify how cognitive predictors relate to the development and maintenance of PTSD. Such studies would also allow for the inclusion of prospectively measured prior beliefs and coping and for investigation of the cognitive factors that predict longer term outcomes for those with traumatic stress reactions.