| Data collection method: |
"Study Design
This was a longitudinal cohort study. Over an 18 month period data were collected via two online questionnaires, one antenatal and one postpartum, and by retrieving participants’ routinely collected birth data from participating sites’ digitally held records.
Setting
All National Health Service (NHS) Hospitals in England with an obstetric maternity unit, or alongside midwife-led units, or stand-alone midwife-led units were eligible to participate. A total of 24 primary care NHS Hospitals (sites) across England chose to be included. Participant recruitment took place concurrently at multiple independent sites.
The study opened to participant recruitment and data collection at the first participating site on 31st December 2020. This was following a delay caused by research measures imposed in the United Kingdom (UK) to help tackle the novel coronavirus pandemic. Data collection closed 30th June 2022.
Study Population
Eligibility Criteria
This study aimed to recruit healthy nulliparous women between 18 and ≤40 years of age, experiencing an uncomplicated pregnancy, and planning a hospital birth. Participants were required to understand and read English, be between 25 and 33 weeks and 6 days gestation and have internet access and an email address for study correspondence.
The age range was chosen to reflect the study focus on uncomplicated pregnancies. Women outside this age range are more likely to require medical assessment, intervention or, at the lower age range require additional support.
Women who chose to take up the invitation to be included accessed the study online either by themselves or with the assistance of the midwife researcher.
Exclusion Criteria
Women who were under ongoing care from an obstetrician, aged 41 or over, with current or pre-existing mental health condition requiring current medication or specialised care, or already participating in a study providing pain management or labour support interventions were excluded.
Sampling Method, Sample Size
The sampling technique was nonprobability, convenience sampling. The sample size was determined by considering previous studies that used the PCS as an assessment tool [12,16,17]. Studies have used various cut-off scores of between ≥20 [12,16] and ≥30 [12,17] for diagnosis of pain catastrophising. Considering a 47.5% prevalence of pain catastrophising found in a non-pregnant population using the cut-off point of ≥20 [12], a cut-off point also used with a pregnant population [16], a power calculation determined the sample size of 384 participants which would give us 90% power to determine association with hospital admission.
This study aimed to recruit 768 women to allow for potential loss to follow-up or changes in risk status from low to high during the antenatal period.
The Measures
Demographics
The demographic profile of participants helped provide context which aided understanding about the findings from this study. Demographic details, included:
• Relationship/Marital status
• Ethnicity
• Employment status
• Highest level of education achieved
Supplement contextual questions included:
• If they had ever been pregnant before but unfortunately suffered a miscarriage or termination of pregnancy before 24 weeks pregnant
• Their current gestation
• A brief pain experience history, including antenatal pain level using an 11 point Numerical Rating Scale (NRS) for intensity ratings from 0 (no pain) to 10 (very severe pain). The NRS was chosen for its reliability and because it is easy to administer and score [18]
The Pain Catastrophising Scale (PCS)
The PCS is one of the most widely used psychometric measures of catastrophic thinking linked to pain [8,17,19]. The PCS is a self-report measure developed for both clinical and non-clinical use. It is composed of 13 items based on catastrophising definitions described in the literature, and previous experimental and clinical research on catastrophic thinking in connection to pain experience [17]. PCS scores have been found to correlate with other health measures, including pain intensity, pain-related disability, and psychosocial distress [20]. The 13 items are divided into three dimensions (subscales): helplessness, magnification and rumination. The correlational relationship between these dimensions has been replicated in several investigations demonstrating internal consistency and validity of the three subscales with total PCS Cronbach’s coefficient alphas = 0.87, rumination = 0.87, magnification = 0.66, and helplessness = 0.78 [21] and it has a high test-retest correlation of r=0.75 across 6 weeks [17].
For each of the 13 items participants are required to reflect on past painful experiences and score their thoughts or feelings on a 5-point Likert scale between “not at all” (score 0), and “all the time” (score 4). The highest possible total score is 52. The higher the score the greater the catastrophic thinking. Although pain catastrophising scores have been shown to be normally distributed, the PCS developers have predominantly taken a score of 30 or more to determine pain catastrophising as clinically relevant [17] with other studies finding lower cut-off scores are clinically relevant [16].
The Wijma Delivery Expectancy Questionnaire WDEQ-A
The Wijma Delivery Expectancy Questionnaire Part A (WDEQ-A) [22] asks women about their cognitive and emotional beliefs about childbirth. It is a self-report measure with 33 items, each item rated on a 6-point Likert scale ranging from ‘‘not at all’’ to ‘‘extremely’’. The minimum total score is 0 and the maximum is 165. The higher the score the greater the fear with a cut-off point of 85 or above indicating clinically relevant FOC [10,23]. The internal consistency of the WDEQ-A has been found to be strong with a Cronbach’s coefficient alpha of 0.87 [22] and 0.94 [10].
Although the WDEQ-A has been criticised for its multidimensionality [24] and its phraseology for use with UK women [25], the WDEQ-A was chosen in the absence of a more fitting measure of FOC. It is perceived by women as a thorough tool which captures most of women’s fears [25] and has demonstrated good reliability and validity [26]. It is one of the most widely used tools worldwide in assessing FOC [26,27] and has also shown to correlate well with other FOC measures in identifying high childbirth fear in first time mothers, previous emergency caesarean and women with self-reported anxiety and/or depression [10].
Postnatal Questionnaire (PNQ)
Participants were asked to complete a second online survey at approximately 3 weeks postpartum, or 3 weeks after their expected due date if they had their baby early. The majority of woman completed the PNQ between 21-28 days.
Prior to its use the postnatal questionnaire was pretested with four pregnant women, two birthing partners, two non-pregnant multiparous women of childbearing age, four maternity support workers and nine clinical maternity experts.
For this study participants were asked to provide data on their latent phase (which is not routinely collected in the NHS), including cervical dilatation on admission.
Recruitment
A pragmatic approach was taken for participant recruitment allowing sites to use various methods such as posters, social media, or direct invitation by relevant staff, or a combination of methods."
V Bartholomew, V Hundley, C.J Clark, B.A Parris,
The RETHINK Study: Could pain catastrophising explain why some women are more likely to attend hospital during the latent phase of labour,
Sexual & Reproductive Healthcare,
Volume 39,
2024,
100941,
ISSN 1877-5756,
https://doi.org/10.1016/j.srhc.2023.100941. |
| Data processing and preparation activities: |
Original scores collected for the Fear of Childbirth have been included in the dataset as have the adjusted scores, as per the designers of this questionnaire (Wijma et al 1998) instructions. These adjusted scores were used in the analyses.
(Wijma, K., Wjma, B. and Zar, M., 1998. Psychometric aspects of the W-DEQ; a new questionnaire for the measurement of fear of childbirth. Journal of Psychosomatic Obstetrics and Gynaecology, 19 (2), 84-97). |
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