Table 1

Outline of measures used for data collection

Mother only measures
MeasureDetails of measureData relating toHypothesis
Index admissionOne-month postdischargeOne-year postdischarge
Clinical diagnosisCase record data on participants’ clinical diagnoses.*X
Brief Psychiatric Rating Scale-Expanded24-item measure that assesses positive, negative and affective symptoms among people with a mental illness39; individual item scores are summed, with higher scores indicative of more severe symptomology. For this study, we use case record data for the index episode* and have modified the scoring criteria so that responses are either ‘present’ or ‘absent’, with a score of 1 or 0, respectively.X
Mental Health Act detentionsCase record data on Mental Health Act Status*, supplemented by self-report.†XX
Threshold Assessment Grid (TAG), including safeguarding risks to children7-item scale that assesses the severity of a person’s mental health problems and clinical risk (safety, risk, needs and disabilities).40 We modified the TAG to include an additional item on safeguarding risks to children. Scores on the modified TAG range from 0 to 28, with lower scores indicating less severe symptoms.40 Ratings of severity of illness (using TAG applied to case notes) are reached by consensus among the research team, to make severity ratings (in the nature subjective) as consistent and reliable as possible.*X
Health of the Nation Outcome ScaleClinician rated scale of health and social functioning of people with severe mental illness in 12 domains (scales)41 with each scale rated from 0=‘no problem’ to 4=‘severe to very severe problem’.*XX
Readmissions and CRT service useCase record data on readmissions to MBUs or generic acute wards and CRT contacts in the year postdischarge*, supplemented by self-report data.†XPrimary
Drug and alcohol misuseCase record data on drug and alcohol misuse*, supplemented by self-report data.‡X
Safeguarding category of infantCase record data* and social care data§, supplemented by self-report data‡, on safeguarding status of infant(s) and other children for the index admission and 1-month postdischarge period, and safeguarding status of the index infant at 1-year follow-up.XXXSecondary
Sociodemographic and clinical factorsSelf-report data†‡ and case record data* on sociodemographic/clinical factors, including: age, ethnicity, social class, income, partner status, previous parenting experience, current clinical psychiatric diagnosis, previous psychiatric and medical history (eg, no of acute service contacts in 2 years prior to index admission).XXX
Modified Pathways to Admission questionnaireSelf-report‡ (supplemented by case record data*) questionnaire of pathways to care following a mental health crisis in the perinatal period,33 including service use and contact in the days preceding admission and the circumstances leading up to admission for the current crisis.X
Adapted Adult Service Use Schedule (AD-SUS)Researcher-administered‡ schedule42 measures individual-level resource use, including service use by the infant and services related to the birth. It records all-cause hospital and community-based health and social care services, plus mental health related medication use. Specifically, this includes the use of any of the following for the women and/or her index baby: accommodation (provided by the NHS or Local Authorities), services for looked after children (fostering, adoption, formal kinship, etc), inpatient stays, outpatient appointments, day patient contacts, accident and emergency contacts, community health and social care contacts and mental health related medication. The AD-SUS covers the period of the index admission to 1-month postdischarge period. The adapted AD-SUS was piloted in the relevant population as part of the Effectiveness and cost-effectiveness of Mother and Baby Units versus general psychiatric inpatient wards and Crisis Resolution Team services (ESMI) study National Institute for Health Research programme development grant (RP-DG-1108–10012).XPrimary
Camberwell Assessment of Need for Mothers (short version)Researcher-administered‡ 26-item questionnaire that assesses the health and social care needs for mothers with severe mental illness,43 scored on a scale of either 1=‘met need’, 2=‘unmet need’ or 0=‘no problem’; the sum of the ‘met need’ and ‘unmet need’ items generate a total score of the number of needs.XXSecondary
Modified Composite Abuse ScaleSelf-report‡ 30-item questionnaire assessing experiences of partner abuse.44 Items are rated from 0=‘never’ to 5=‘daily’, with total scores ranging from 0 to 150. A cut-off point of 3 is assigned, with scores of 3 or more indicating partner violence. The scale has been modified for this study to collect data covering the two time periods: (1) prior to admission and (2) since discharge.XX
Modified Social Provisions ScaleResearcher-administered‡ 24-item questionnaire that assesses the degree to which an individual’s social relationships provide various dimensions of social support.45 Items are rated on a four-point Likert scale ranging from 1=‘strongly disagree’ to 4=‘strongly agree’.45 6 domains of social provision (ie, guidance, reassurance of worth, social integration, attachment, nurturance and reliable alliance) are calculated by summing the scores of specific items on the questionnaire; high scores on each of the domains indicate that the person is receiving that social provision. The scale has been modified to collect data covering the two time periods of interest for the study: (1) prior to admission and (2) since discharge.XX
Short Form 36 Health SurveySelf-report‡ 36-item questionnaire which produces a preference-based single index measure of general health.46 It measures health on eight multi-item dimensions: (1) limitations in physical activities because of health problems; (2) limitations in social activities because of physical or emotional problems; (3) limitations in usual role activities because of physical health problems; (4) bodily pain; (5) general mental health (psychological distress and well-being); (6) limitations in usual role activities because of emotional problems; (7) vitality (energy and fatigue) and (8) general health perceptions.47 This measure can be used to calculate quality-adjusted life years (QALYs).XPrimary
EuroQol five-dimension scale (EQ-5D-5L)Self-report†‡ preference-based measure of health-related quality of life measured on five dimensions (mobility, self-care, usual activities, pain/discomfort and anxiety/depression), each rated on five levels (no problems, slight problems, moderate problems, severe problems and extreme problems).48 This measure can be used to calculate QALYs.XXPrimary
Perinatal VOICE questionnaire27-item self-report‡ questionnaire that examines admission processes and therapeutic activities on wards. It contains six sections relating to experience of care on admission: (1) care and treatment (three items); (2) medication (two items); (3) staffing (seven items); (4) environment (five items) and (5) baby’s well-being (10 items). At the end of each section, respondents are encouraged to provide further comments about their experience of care.XSecondary
Client Satisfaction QuestionnaireSelf-report‡ questionnaire49 of experiences of health service use. Eight items are rated on a four-point scale and explore degrees of service satisfaction (eg, ‘how would you rate the quality of service you received?’ ‘How satisfied are you with the amount of help you received?’); higher scores indicate greater satisfaction. We asked a further two items to assess the satisfaction of care in relation to the baby (‘How satisfied were you with the advice you received about your baby from the service?’) and a free-text feedback item on the most and least helpful aspects of service use (‘what were the most/least helpful aspects of the service?’).XSecondary
The Postpartum Bonding QuestionnaireSelf-report‡ 25-item questionnaire designed to provide an early indication of disorders within mother–infant relationships, through the assessment of a mother’s feelings and attitudes towards her infant.50 Individual items are rated on a six-point scale (0–5) and are used to obtain four subscale scores: (1) impaired bonding (12 items, scores ranging from 0 to 60), (2) rejection and anger (seven items, scores ranging from 0 to 35), (3) anxiety about care (four items, scores ranging from 0 to 20) and (4) risk of abuse (two items, scores ranging from 0 to 10); higher scores indicate increased difficulties.XSecondary
Childhood Trauma QuestionnaireSelf-report‡ 28-item questionnaire designed to assess five types of negative childhood experiences: (1) emotional neglect, (2) emotional abuse, (3) physical neglect, (4) physical abuse, and (5) sexual abuse.51 Items are rated on a five-point scale (–5), from ‘never true’ to ‘very often true’, with scores ranging from 5 to 25 for each of the abuse types.X
Mother/infant measures
Mother–infant interactionsMother–infant interactions are captured in a 3 min video clip taken during play at home‡ and subsequently assessed by a trained rater, unaware of participant service use, using the Child and Adult Relational Experimental Index.52 Coding of the interaction takes between 15 and 20 min and focuses on seven aspects of both mother and infant behaviour: (1) affection; (2) body contact; (3) facial expression; (4) verbal expression; (5) turn-taking; (6) control and (7) developmental appropriateness of chosen activity). Each aspect of mother and infant behaviour is evaluated individually and summed to make seven scale scores, with each scale scored on a range from 0 to 14. For mothers these scales are sensitivity, control and unresponsiveness and for infants these scales are cooperativeness, compulsivity, difficultness and passivity. Higher scores of control and unresponsiveness on the mother scales and higher scores of compulsivity, difficultness and passivity on the infant scales are indicative of poorer dyadic synchrony. Higher scores of sensitivity on the mother scale and higher scores of cooperativeness on the infant scale are indicative of stronger dyadic synchronyXSecondary
Bayley Scales of Infant DevelopmentResearcher-administered scales‡ that examine motor (fine and gross), language (receptive and expressive) and cognitive development of infants and toddlers.53 X
Infant growth trajectoriesCase note data on infants APGAR scores and early weight measurements‡X
  • *indicates that these data are extracted from clinical case records.

  • †indicates that these data are collected at a 1-year follow-up telephone interview.

  • ‡indicates that these data are collected at a 1-month postdischarge face-to-face interview.

  • §indicates that these data are collected from social care records.

  • CRT, crisis resolution team; MBUs, mother and baby units; NHS, National Health Service.