Melodies for Mums to Be: Community Group Singing Intervention for Pregnant Women With Antenatal Depressive Symptoms (M4M2B)

Participants randomised to the immediate access arm will receive immediate antenatal access to the six-week group singing intervention, offered alongside existing care.

Melodies for Mums to Be (M4M2B) is a community-based group singing intervention delivered by Breathe Arts Health Research, based on the Melodies for Mums model. The intervention consists of six weekly group singing sessions delivered in community cultural venues across London, in groups of up to 15 participants. Sessions last approximately 60 minutes and are facilitated by trained Breathe artists with experience delivering perinatal singing interventions. Each session includes guided group singing, breathing and relaxation exercises, and opportunities for informal peer interaction. The repertoire is designed to be accessible regardless of musical experience and may include songs drawn from diverse cultural and musical traditions. Sessions are facilitated in English throughout.

• M4M2B

Participants randomised to the delayed access arm will not attend antenatal singing sessions and will receive usual care during pregnancy. They will complete the same antenatal assessment schedule as participants in the immediate access arm. The delayed access arm will be offered the same six-week singing intervention postnatally, commencing after completion of the 8-week postpartum assessment.

Melodies for Mums to Be (M4M2B) is a community-based group singing intervention delivered by Breathe Arts Health Research, based on the Melodies for Mums model. The intervention consists of six weekly group singing sessions delivered in community cultural venues across London, in groups of up to 15 participants. Sessions last approximately 60 minutes and are facilitated by trained Breathe artists with experience delivering perinatal singing interventions. Each session includes guided group singing, breathing and relaxation exercises, and opportunities for informal peer interaction. The repertoire is designed to be accessible regardless of musical experience and may include songs drawn from diverse cultural and musical traditions. Sessions are facilitated in English throughout.

• M4M2B

Participants will receive usual care during pregnancy.

The Edinburgh Postnatal Depression Scale (EPDS) is a 10-item self-report questionnaire developed to detect depression in the perinatal period, and is validated for use in pregnancy. For each statement, women choose one of four responses that best describes how they have felt over the past week. Each item is scored 0 to 3; total scores range from 0 to 30, with higher scores indicating more severe depressive symptoms.

The Maternal Antenatal Attachment Scale (MAAS) is a 19-item self-report questionnaire assessing a pregnant woman's thoughts and feelings towards her unborn baby, covering the quality of attachment and the intensity of preoccupation with the baby. Total scores range from 19 to 95, with higher scores indicating stronger maternal antenatal attachment.

The Prenatal Marschak Interaction Method (Prenatal MIM) is a 15-20 minute video-recorded observational assessment in which the mother completes a series of structured tasks directed at her unborn baby (e.g., talking to, touching and singing to the baby). Recordings are coded by trained coders using the Emotional Availability Pregnancy Screener (Emotional Availability Scales, 4th edition). Two dimensions are rated: Sensitivity (e.g., affect, responsiveness to the baby, bodily attunement, acceptance and amount of interaction) and Non-hostility (e.g., absence of negativity, disrespectful remarks or hostile themes). Each dimension is scored from 1 to 7, with higher scores indicating greater maternal sensitivity and lower hostility towards the unborn baby.

The Edinburgh Postnatal Depression Scale (EPDS) is a 10-item self-report questionnaire measuring depressive symptoms. Each item is scored 0 to 3; total scores range from 0 to 30, with higher scores indicating more severe symptoms. Change is assessed across all study timepoints.

The Patient Health Questionnaire-9 (PHQ-9) is a 9-item self-report questionnaire based on the diagnostic criteria for major depression. Respondents rate how often they have been bothered by each symptom over the past two weeks, from 0 (not at all) to 3 (nearly every day). Total scores range from 0 to 27, with higher scores indicating more severe depressive symptoms.

The Generalised Anxiety Disorder 7-Item Scale (GAD-7) is a 7-item self-report questionnaire measuring symptoms of generalised anxiety. Respondents rate how often they have been bothered by each symptom over the past two weeks, from 0 (not at all) to 3 (nearly every day). Total scores range from 0 to 21, with higher scores indicating more severe anxiety symptoms.

The Perceived Stress Scale (PSS) is a 10-item self-report questionnaire measuring the degree to which situations in one's life over the past month are appraised as unpredictable, uncontrollable and overloading. Each item is rated from 0 (never) to 4 (very often), with positively worded items reverse-scored. Total scores range from 0 to 40, with higher scores indicating greater perceived stress.

The Difficulties in Emotion Regulation Scale - Short Form (DERS-16) is a 16-item self-report questionnaire assessing difficulties in emotion regulation, including emotional clarity, acceptance of emotional responses, impulse control, goal-directed behaviour when distressed and access to effective regulation strategies. Each item is rated from 1 (almost never) to 5 (almost always). Total scores range from 16 to 80, with higher scores indicating greater difficulties in emotion regulation.

The Body Understanding Measure for Pregnancy Scale (BUMPS) is a 19-item self-report questionnaire measuring body image during pregnancy across three subscales: satisfaction with appearing pregnant, concerns about weight gain and the physical burden of pregnancy. Total scores range from 19 to 95, with higher scores indicating greater body dissatisfaction.

The Multidimensional Scale of Perceived Social Support (MSPSS) is a 12-item self-report questionnaire measuring perceived support from family, friends and a significant other. Each item is rated from 1 (very strongly disagree) to 7 (very strongly agree). Total scores range from 12 to 84, with higher scores indicating greater perceived social support.

The Acceptability of Intervention Measure (AIM) is a 4-item self-report implementation outcome measure assessing how acceptable participants find the intervention. Each item is rated from 1 (completely disagree) to 5 (completely agree), and the score is the mean of the items, ranging from 1 to 5, with higher scores indicating greater acceptability. Collected during the intervention phase only (antenatally for the immediate access arm; postnatally for the delayed access arm), and from both arms at 12 months postpartum.

The Intervention Appropriateness Measure (IAM) is a 4-item self-report implementation outcome measure assessing how appropriate (fitting, suitable) participants find the intervention. Each item is rated from 1 (completely disagree) to 5 (completely agree), and the score is the mean of the items, ranging from 1 to 5, with higher scores indicating greater appropriateness. Collected during the intervention phase only (antenatally for the immediate access arm; postnatally for the delayed access arm), and from both arms at 12 months postpartum.

The Feasibility of Intervention Measure (FIM) is a 4-item self-report implementation outcome measure assessing how feasible (workable, possible to take part in) participants find the intervention. Each item is rated from 1 (completely disagree) to 5 (completely agree), and the score is the mean of the items, ranging from 1 to 5, with higher scores indicating greater feasibility. Collected during the intervention phase only (antenatally for the immediate access arm; postnatally for the delayed access arm), and from both arms at 12 months postpartum.

Number of eligible participants who sign up to the intervention.

Number of participants adhering to the intervention and drop-outs measured weekly.

Maternal salivary cortisol concentration (nmol/L), measured by immunoassay in saliva samples collected at home using Salivettes at six points across one day: at awakening, 15, 30 and 60 minutes after awakening, at midday and at 8pm, to characterise the diurnal cortisol profile. Collected from participants who consent to biological sampling.

Infant salivary cortisol concentration (nmol/L), measured by immunoassay in saliva samples collected at home by the mother using infant swabs at two points across one day: at awakening and at 8pm. Collected from infants of participants who consent to infant biological sampling.

Maternal salivary cortisol concentration (nmol/L), measured by immunoassay in saliva samples (Salivette) collected on site immediately before and immediately after the singing session. Collected during the intervention phase only (antenatally for the immediate access arm; postnatally for the delayed access arm).

Maternal salivary oxytocin concentration (pg/mL), measured by immunoassay in passive drool saliva samples collected on site immediately before and immediately after the singing session. Collected during the intervention phase only (antenatally for the immediate access arm; postnatally for the delayed access arm).

The Maternal Postnatal Attachment Scale (MPAS) is a 19-item self-report questionnaire assessing a mother's thoughts and feelings towards her infant, covering the quality of attachment, absence of hostility and pleasure in interaction. Total scores range from 19 to 95, with higher scores indicating stronger maternal attachment to the infant.

The Crittenden Child-Adult Relationship Experimental Index (CARE-Index) is a validated observational tool for assessing parent-infant interaction. A 3-minute video recording of the mother and baby in free play is coded by trained coders. The interaction is rated on scales of 0 to 14 for maternal behaviour (sensitivity, control and unresponsiveness), infant behaviour (cooperation, compulsivity, difficultness and passivity) and dyadic synchrony. Higher maternal sensitivity, infant cooperation and dyadic synchrony scores indicate more attuned interaction; higher maternal control and unresponsiveness, and higher infant compulsivity, difficultness and passivity scores indicate less attuned interaction.

The Parental Cognitive Attributions and Mentalization Scale (PCAMS) is a validated tool for assessing the quality of parental communication. Maternal speech during a 3-minute video recording of the mother and baby in free play is coded by trained coders, across three domains: mentalising comments (the mother's awareness and interpretation of her infant's cognitive, emotional and physiological states); attentional focus (infant-, parent- or other-focused speech); and affective connotation (positive or negative comments). Each category is reported as a proportion (0 to 100%) of maternal comments. Higher proportions of mentalising and infant-focused comments indicate more sensitive, supportive communication; higher proportions of negative or parent-focused comments indicate less sensitive communication.

The Couple Satisfaction Index - Short Form (CSI-16) is a 16-item self-report questionnaire measuring satisfaction with a romantic relationship, including happiness, warmth and closeness in the relationship. Total scores range from 0 to 81, with higher scores indicating greater relationship satisfaction.

The Parenting Stress Index, Fourth Edition Short Form (PSI-4-SF) is a 36-item self-report questionnaire measuring stress within the parent-child system across three subscales: parental distress, parent-child dysfunctional interaction and difficult child. Each item is rated from 1 (strongly disagree) to 5 (strongly agree). Total stress scores range from 36 to 180, with higher scores indicating greater parenting stress.