This study was a non-blinded, prospective, observational, pilot randomized controlled study. Mothers with preterm babies admitted to the Stollery Children Hospital NICU, Royal Alexandra site, were eligible to enter the study if (a) fluent in spoken and written English, (b) the baby had an anticipated stay at this NICU for at least four weeks following recruitment, (c) if the baby's medical condition allowed KC at recruitment, (d) if the mother was available for regular KC during the four weeks after recruitment, and (e) if mother agreed to receive teaching for 30–45 min weekly during those four weeks. Mothers who reported current active mental illness and current or prior substance abuse/addiction were excluded. Given the pilot nature of this study, a power analysis was not done. We aimed to recruit a convenience sample of 30 participants (15 per group) . The study was approved by the Regional Ethical Review Board at the University of Alberta (study code: Pro00089053). This study was retrospectively registered on January 6th, 2021, at clinicaltrials.gov (registration number: NCT04696770).
To optimize enrolment, the NICU Social Workers, who meet with all families in the NICU during the first days of admission, were asked to introduce this pilot study to mothers, then inform the research team of their potential interest. Once recruited, mothers were randomized into the Mindful Kangaroo Care (MKC) group or the Standard Care (SC) group. To avoid selection bias, we used block randomization using random block sizes . Sealed envelopes were prepared and shuffled by one team member. Each envelope contained the group allocation for one study subject and the allocation was revealed after consent and recruitment.
Mothers in the MKC group had face-to-face direct mindfulness coaching during weeks 1 and 2, and ongoing support during weeks 3 and 4. The principal investigator is a Unified Mindfulness certified lead coach . During the first encounter, mothers learnt an introductory mindfulness technique to develop the awareness of any sensations felt in the body while holding their baby in KC, with an emphasis on the physical sensations created by the presence of their baby. At the second encounter, mothers learnt a mindfulness technique to create positive emotional sensations in the body triggered by holding their baby skin-to-skin. In both cases, the baby was at the centre of the mindfulness practice. Additionally, mothers had access to downloadable audio files of both techniques' instructions and guided practice sessions (duration 16 & 21 min). See Additional files 1, 2, 3 and 4 for the written script of those audio files.
Mothers in the control group received Standard Care which, in this NICU, includes KC according to bedside staff's judgement of baby and mother readiness for KC. SC mothers did not receive any mindfulness coaching but had a weekly visit to encourage them to fill out the KC log.
All mothers were asked to complete a general demographic form at enrolment and a KC Log, on which they were asked to record the timing and duration of each KC session and document concurrent activities during KC. The demographic form and the KC logs for both the intervention and the control groups developed specifically for this study are provided as Additional files 5, 6 and 7 respectively.
Mothers were asked to complete the following questionnaires at enrolment (Pre) and four weeks after enrolment (Post):
(A) To evaluate stress, mothers filled out the Parental Stressor Scale for NICU parents, a validated situation-specific scale for parents who have a baby hospitalized in NICU. Parents rate sources of stress within three domains: sights and sounds, infant behaviour and appearance, and parental role alterations—scores for each question range from 1 (not at all stressful) to 5 (extremely stressful). A higher score indicates a higher level of stress . The Parental Stressor Scale for NICU parents is copyrighted and permission was obtained to use it for this study.
(B) To evaluate symptoms of depression and anxiety, mothers filled out the Patient Health Questionnaire 4, a four-item validated and standardized questionnaire to measure depression and anxiety in the general population—scores for each question range from 1 (not at all) to 4 (nearly every day). A higher score in each category suggests anxiety or depression accordingly [20, 21]. The Patient Health Questionnaire 4 is public domain and free to use for all clinical and research purposes.
(C) To evaluate mindfulness, mothers filled out the 13-item Toronto Mindfulness Scale developed and validated to measure the state of mindfulness. It measures two components: curiosity and decentering the awareness of one's experience. The curiosity questions correspond best to the awareness of the present moment, while the decentering questions correspond best to a non-judgmental attitude. The awareness of the present moment and a non-judgmental attitude are two key components of mindfulness—scores for each question range from 0 (not at all) to 4 (very much). A higher score indicates a higher level of mindful awareness . The Toronto Mindfulness Scale is public domain and available to use for all research purposes.
(D) Mothers were asked to complete an acceptability form, a 3-point Likert scale created by the research team, measuring their acceptability of the different instruments and mindfulness intervention. The acceptability form created for this study is provided as Additional file 8.
The research team also maintained a feasibility form for every mother recruited with the following components: recruitment capability, data collection procedures and outcome measures, resources and ability to implement the study [23, 24]. The feasibility form developed for this study is provided as Additional file 9.
Study data were managed using Research Electronic Data Capture, a secure, web-based software platform hosted at the University of Alberta [25, 26]. Group demographics were compared with t-test, chi-square and Mann–Whitney U as appropriate. The scores of the three questionnaires were analyzed with the Wilcoxon Signed-Rank test for within-group comparison and the Mann–Whitney U test for between-group comparisons, given the small n and ordinal nature of the questionnaires' scores. We used the Spearman correlation test in the MKC group for correlation between the mindfulness scores and the stress, anxiety and depression scores. 2-tailed p-values were used.