Personality refers to individual differences in characteristic patterns of behaving, feeling, and thinking [30]. There have been several cross-sectional and longitudinal studies investigating the relationship between personality and various health behaviors in the general population. The present research examined the correlations between personality and persistent PGP after the pregnancy by analyzing a sample of 264 (30.3%) women with a two-year follow-up period. Lower extraversion and conscientiousness, and higher neuroticism, were demonstrated to be correlated with continuous PGP for up to 2 years. In present cohorts, higher neuroticism and lower conscientiousness generally have a close association with more intensive pain levels, and increasing evidence of this association has been revealed in non-clinical samples [32, 33]. There is also some evidence that extraversion has a close connection with decreased pain feelings [34, 35]. Similarly, the current study adds that personality could prospectively predict who would bear more risks for sustained PGP in the two years after the childbirth.
Both physical and psychological factors could strength the correlations between pain scores and personality traits. Patients with chronic disease, for instance, generally tend to suffer from tremendous pain and stress [31, 32]. The negative feeling is also considered a risk factor for immense pain over time [34]. Patients lower in conscientiousness and extraversion, and higher in neuroticism may have a more significant burden on chronic disease [36–38].
Based on this, there are at least three reasons why personality traits could lead to an increased risk of sustained PGP. First, enhanced sensitivity to pain feeling exists in some personality traits. A person would report different pain intensity even if the stimulus is constant [39]. Those who tended to be neurotic could show increased sensitivity for experiencing pain, which thus makes them suffer more from it. One experimental study showed that highly neurotic persons reported more pain than those who were less neurotic under the same laboratory-induced stimuli [40]. In another pain experiment, neuroticism was associated with more intense pain, which sustained a week after the stimulation [41]. The findings suggest it is more likely for neurotic individuals to have a less easily diminished experience of pain feelings over time.
Second, emotional stability is manifested as a particular subject's tendency towards negative emotion, depression, and anxiety. Extraversion and neuroticism are demonstrated as the two emotional traits most closely connected with negative feelings. Subjects who are more reactive and less emotionally stable are more likely to have adverse reactions. A tendency to be emotionally unstable is common in those who are highly neurotic [41]. Studies have indicated that mothers with low scores in emotional stability are more likely to prefer a cesarean delivery and have complications during delivery, including failure to progress, foetal distress, and severe tearing [41, 43]. The present results further find that high neuroticism relates to persistent PGP. The extraversion is inclined not to be associated with pain sensitivity in response to a stimulus [40, 41]. Extraversion tends to affirmative emotions, sociability, and high activity. These characteristics could give impetus to join sports club such as swimming, yoga, and be more willing to share experience about PGP's alleviation method, which has been demonstrated to help recovery from chronic pain [37, 41]. Third, personality affects health-related behaviors, which could be related to pain.
Strong evidence has been found that conscientiousness, extraversion, and neuroticism have connections with some behaviors that make the risk of experiencing pain arise [39, 42, 43]. For instance, patients high in conscientiousness, responsible, self-disciplined, and inclined to adhere to social norms, consume less alcohol and fewer cigarettes than average [42, 43]. Higher neuroticism and lower extraversion tend to have physical inactivity [42], poor sleep patterns [43], and tobacco use [44]. These behavioral factors have also been demonstrated to aggravate pain [42–44].
Perinatal depression is a common mental disorder in pregnancy and lactation, with a prevalence between 8% and 36% around the world. This condition could threaten the health of pregnant women and even children [45]. In order to diminish the influence of depression as a confounder for the PGP [46], patients who had many psychological, psychosocial, socioeconomic, and obstetric risk factors reported to be connected with this mental disorder in previous studies [44–46] were excluded as soon as possible (see exclusion criteria mentioned above).
The current study included several advantages, such as a measurement of five personality traits, a relatively prospectively long-term assessment of pain, and a focus on pregnant women suffering PGP. These complement the vacancy related to pregnancy-related LBP in previous research. To our knowledge, this is the first study that investigated the associations between personality traits and pregnant women with continued PGP. There are some clinical implications. This study helps the practitioner identify who is most at risk for persistent PGP. Specifically, the present results revealed that individual differences in psychological dispositions are closely related to PGP and its prognosis. Such findings may also be useful for interventions. For instance, interventions themselves might depend on the individual’s personality. Despite not demonstrated in the present study, personality-based interventions have been used smoothly in other fields, such as prevention programs for adolescent alcohol use and misuse [47], and improving behavioral symptoms of dementia [48].
There were several limitations to our study. First, the confounding factor could compromise the reliability of the results, particularly for the potential risk factors for perinatal depression. The etiology of pregnancy-related depression is multifactorial and complex. Despite trying to control its potential risk factors as much as possible, it is unrealistic to eliminate all the adverse events and its effect on each subject’s life. Second, we didn't adjust the P-value for multiple comparisons. While adjusting p values contributes to minimizing the Type I errors, such adjustments can be overly conservative and increase the Type II errors. Last, our assessment of maternal personality traits was completed using a standard tool, the QBFPT developed by Vermulst and Gerris. However, there are several other measures in which they have a specific difference in descriptions about the personality traits. A future study about comparing the reliability and accuracy among them is needed. These limitations bring up the necessity of further studies.