This is a multicenter randomized controlled trial (RCT) with two parallel groups: (1) adapted MBCP educational course with compassion practices delivered for pregnant women and their partners + TAU; and (2) TAU only, which consists of a childbirth education course provided by PC midwives. This protocol has followed the SPIRIT guidelines  Additional file 1. The trial registration number of the study is ClinicalTrials.gov NCT03247491.
Setting and study sample
Participants will be pregnant women in the second trimester of pregnancy living in the city of Valladolid (Spain) who are served by the Spanish NHS. Partners of the expectant women will be encouraged to participate in the courses. Participants considered for inclusion will be: (1) women in weeks 6–25 of pregnancy; (2) able to read, write, and understand Spanish; (3) age ≥ 18 years ; and (4) have signed a written informed consent document following an informed consent procedure. Exclusion criteria will include: (1) any diagnosis of disease that may affect the central nervous system, such as brain pathology or traumatic brain injury; (2) other psychiatric diagnosis or acute psychiatric illness, such as substance dependence or abuse, a history of schizophrenia or other psychotic or eating disorders; (3) any medical, infectious, or degenerative disease that may affect mood; (4) presence of delusional ideas, hallucinations, or at risk for suicide; and (5) currently under psychopharmacological medication or under psychopharmacological treatment.
The sample size estimation was based on the expectation of a moderate standardized mean difference between groups on depressive symptoms at post-birth of d = 0.59. Like the protocol that will be used in the present study, this effect size was found in a recent RCT that used a modified MBCP program  compared to a TAU active standard childbirth preparation course with no mind–body components. This effect size is also similar to that obtained in other studies using other programs , a pilot study evaluating the effectiveness of MBCE , a cohort study assessing the MindBabyBody program , and a brief pilot adaptation based upon the MBCP program . Considering a statistical power of 80%, a 5% significance level in a between-group interaction with a local alpha of 0.017 in the first test—using Benjamini–Hochberg’s procedure—and a dropout rate in the range of 15%–20%, as has been observed in these types of studies , 61 participants are needed in each group, for a total sample size of 122 women.
Participants will be recruited from 11 PC urban healthcare centers in the city of Valladolid, Spain through referrals from midwives and obstetricians. When a health provider identifies a pregnant woman who might be a potential participant, they will facilitate contact with the primary study researcher who will arrange a meeting with both the pregnant woman and her partner. During this interview, the study characteristics will be explained, including the main objectives, potential benefits and adverse events, an explanation regarding the assigned home meditation practice, and the option to end their participation in the study at any time. Partners will be encouraged to participate in all of the sessions and the assigned home practices. If a pregnant woman is interested in taking part in the study, the researcher will give her an information booklet with additional details describing the trial. Within three days after having signed the written informed consent form, participants will be interviewed by an independent researcher who will administer the MINI International Neuropsychiatric Interview  in order to assess eligibility related to the inclusion and exclusion criteria. If the pregnant woman fulfills all of the study criteria, the same researcher will administer the baseline tests. An independent researcher will conduct the randomization procedure after the baseline assessment. Recruitment will be done consecutively to complete the sample size over an expected 24-month period. Flowcharts giving an overview of the study design and the study timeline are summarized in Figs. 1 and 2, respectively.
Randomization, allocation, and masking of study groups
Women who want to participate in the trial who fulfill the study criteria will be assigned consecutive numbers and will be allocated to one of the two study groups using a simple – not stratified – random number sequence using a computer program generated by a member of the research team who does not know the study aims. The allocation will be carried out by a researcher of the “Primary Care Prevention and Health Promotion Research Network” (REDIAPP) who is not involved in the study. The number sequence will be concealed until intervention groups are assigned. Thus, participants will have to agree to participate in the study before the randomization process and will not be informed of their group allocation until after completion of the pre-treatment measures. Because of the nature of the intervention, participants cannot be blinded to their group allocation. Study personnel conducting psychological assessments will be masked to participants’ treatment conditions and will be specially advised not to ask for this information. The researcher who administers the baseline assessments will be unaware of which treatment group the patient will be assigned. This researcher will be different from the one who will facilitate the rest of study assessments by means of an online procedure. Midwives and obstetricians will be also unaware of the patients’ randomized assigned group for as long as possible. In addition, the statistician who will conduct the primary analysis of the data will be blind to which condition the patient is assigned.
All participants included in the study, whether they receive the adapted MBCP program with compassion practices or not, will be treated by their general practitioner (GP), obstetricians, and midwives according to TAU at a PC level. Women who belong to the same health center will receive the TAU from the same staff. The adapted MBCP program arm will receive a combined treatment, which consists of the MBCP program with compassion practices tailored to the Spanish NHS plus TAU. The program will take place during the second trimester of pregnancy, before participating in the TAU childbirth classes that are taught at their site during the third trimester.
Treatment as usual (TAU)
TAU consists of a childbirth education program that is offered at no charge to pregnant women and their partners by the local midwives in PC facilities in the Spanish NHS. Women usually attend this program in groups of 8–12 couples in the third trimester of pregnancy (during weeks 28–36). It covers basic topics about pregnancy, delivery, postpartum, breastfeeding, and care of a newborn baby. The duration of the TAU course is usually 16 h and includes both information-based classes and some instruction in basic relaxation and breathing techniques to cope with new stressful situations.
Adapted MBCP with compassion practices tailored to the Spanish NHS
The main objective of the MBCP program  is to teach mindfulness meditation for decreasing stress during pregnancy, reducing pain and fear during childbirth, to support parenting with wisdom and compassion, and to interrupt intergenerational patterns of suffering . The course schedule is 3 h once a week for nine weeks, a 7-h silent practice day on the weekend between classes 6 and 7, and a reunion class after all the women have given birth. Although the MBCP program is designed for couples, pregnant women without a partner or whose partner cannot attend are also welcomed, as are pregnant women with other support people. A recommended class size is 8–12 couples. Various formal mindfulness meditation exercises are practiced in each class; participants are also asked to practice the meditations daily at home using audio recordings throughout the course. Formal mindfulness meditation and the attitudes cultivated in a mindfulness practice are fully integrated into the curriculum, which also includes instruction regarding the physiology and mind–body dimensions of pregnancy, labor, childbirth, breastfeeding, adjustment in the postpartum period, and attending to the needs of a newborn. Mind–body pain coping skills for childbirth and awareness skills for coping with stress in daily life are also taught. Other elements include encouraging a sense of connection or community among participants in order to minimize social isolation and its resulting negative effects on the mental health of new parents.
The intervention that will be used in this study is an adaptation of the basic MBCP program to: (1) include an explicit compassion component; and (2) be tailored to fit the Spanish population and the existing NHS programs for expectant women and their partners, improving adherence. It will be implemented at a PC level, with a duration of 10 sessions (eight sessions before childbirth and two sessions after childbirth, at three months and six months postpartum). Each class in this adapted MBCP program is 2 h long. Because all women receive free childbirth education classes from their midwives at their PC center, the adapted MBCP program will offer the mindfulness and compassion meditation practices from the original MBCP program without the childbirth information. In addition, this Spanish adaptation does not include the silent day of mindfulness practice as in the original MBCP program. While the value of this day of practice is clear, it is logistically difficult to implement it within the Spanish healthcare context as the PC facilities are closed during the weekends. However, the practices taught during the day of silence in the foundational MBCP program will be included in class 7. This class 7 has been adapted to cover all the practices offered during the course as well as the silent retreat day, including walking meditation and an interpersonal mindful speaking and listening inquiry between partners. There will be four adapted MBCP groups, with approximately 15 pregnant participants and their partners in each group. All of the classes will be held at same health center location. The total number of hours in the adapted MBCP program, including the TAU, will be 36.
During the adapted MBCP program with compassion exercises, participants will learn 14 formal mindfulness and compassion practices: awareness of breathing meditation; body scan meditation; compassionate body scan meditation; being with baby meditation; mindful yoga; walking meditation; creating a safe place meditation; loving-kindness meditation; sitting meditation; self-compassion meditation; coping with pain ice cube meditations; a three-step breathing meditation; compassionate touch meditation; and interpersonal mindful speaking and listening meditation. Participants will receive audio recordings of each of these practices to be used in their assigned daily home practices. All the participants will be asked to keep a daily diary of their home practice, as well as a calendar of pleasant and unpleasant events. See Appendix for a detailed description of all the elements of the adapted MBCP program.
All participants included in the trial will be assessed at pre-test/baseline, post- intervention, and at three and six months after childbirth (approximately six and 12 months after inclusion). The study instruments that will be used are summarized in Table 1.
The primary outcome will be depressive symptom severity as assessed by the Edinburgh Postnatal Depression Scale (EPDS) . The EPDS is a 10-item self-report scale used to assess the common symptoms of depression (e.g. “I have blamed myself unnecessarily when things went wrong”) during the perinatal period, both pre- and postnatally. It is one of the most widely used instruments to evaluate the severity of PD in clinical trials . Each item of the EPDS is scored on a 4-point scale (from 0 to 3), with the total scale score in the range of 0–30. The validated Spanish version of the EPDS has a cutoff point of ≥ 11 to identify the presence of probable perinatal depression in women, obtaining an area under the curve of 0.98, with also good sensitivity and specificity values .
A list of sociodemographic variables, such as age, marital status, education, occupation, nulliparity, and any previous depression episodes will be collected.
The Perceived Stress Scale (PSS)  is a widely used self-report instrument that evaluates the degree to which situations in one’s life are appraised as stressful. Items are designed to assess how unpredictable, uncontrollable, and overloaded respondents have found their lives to be during the last month. It consist of 14 items (e.g. “In the last month, how often have you found that you could not cope with all the things that you had to do?”) with a 5-point response scale from 0 (“never”) to 4 (“very often”) and a total score in the range of 0–56. Higher scores indicate greater perceived stress. The validated Spanish version of the PSS, which has demonstrated appropriate psychometrics, will be used .
The Positive and Negative Affect Schedule (PANAS)  consists of two 10-item scales that provide measures of positive affect (e.g. “interested”) and negative affect (e.g. “irritable”), with answers ranging in a Likert-type scale from 1 (“very slightly or not at all”) to 5 (“extremely or very much”). Participants are asked to rate the extent to which they have experienced each affective state, resulting in a total score in the range of 10–50. The Spanish version of the PANAS, adapted with adequate psychometrics and designed to assess affective states over the last week, will be used .
The Five Facet Mindfulness Questionnaire (FFMQ)  evaluates five facets of personal disposition towards being mindful in daily life situations. It is composed of 39 items to assess the subscales of observing (e.g. “When I’m walking, I deliberately notice the sensations of my body moving”), describing (e.g. “I’m good at finding words to describe my feelings”), acting with awareness (e.g. “When I do things, my mind wanders off and I’m easily distracted” – item reversed), non-judging of inner experience (e.g. “I make judgments about whether my thoughts are good or bad” – item reversed), and non-reactivity to inner experience (e.g. “I perceive my feelings and emotions without having to react to them”). The FFMQ is rated on a Likert-type scale, ranging between 1 and 5 points (from 1 = “never or very rarely true” to 5 = “very often or always true”). Total scores are in the range of 39–195, being that a high score indicates a high level of dispositional mindfulness. The validated Spanish version of the FFMQ that has demonstrated appropriate psychometric properties will be used .
The Self-Compassion Scale (SCS)  is a self-report measure of self-compassion. It consists of 26 items that assess how respondents perceive their actions toward themselves in times of difficulty, measuring facets of self-kindness (e.g. “I try to be loving towards myself when I’m feeling emotional pain”), common humanity (e.g. “I try to see my failures as part of the human condition”), and mindfulness (e.g. “When I’m feeling down, I tend to obsess and fixate on everything that is going wrong” – item reversed). Items range between 1 (“almost never”) to 5 (“almost always”). The SCS has shown appropriate psychometrics, and it allows for a unidimensional total score in the range of 26–130 . The validated Spanish version of the SCS will be used .
The Parental Evaluation Scale (EEP)  is a self-administered measure to assess self-efficacy feelings about motherhood in women with children aged 0–2 years. It is composed of 10 items (e.g. “I feel like I do a good job as a mother”) that use a 10-point Likert-type scale from 0 (“Totally disagree”) to 10 (“Totally agree”). The EEP gives a global score of maternal self-efficacy in infants’ mothers in the range of 0–100, with higher values indicating greater self-efficacy. The validated Spanish version of the EEP has demonstrated appropriate psychometric characteristics .
The Client Service Receipt Inventory (CSRI)  is a questionnaire for gathering information about the use of healthcare and social services, as well as other economic variables (e.g. time of sickness absence, etc.). The version that will be used in this study has been designed to collect retrospective data on service utilization during the previous six months from baseline assessment and from the six-month follow-up measure. The CSRI-Spanish validated version, that has good psychometric properties, will be used .
Results will be reported according to the CONSORT guideline statement . Sociodemographic data at baseline will be presented by means of frequencies (percentages), medians (interquartile range), and means (SD), according to their level of measurement and statistical distribution. Visual inspection on the baseline data will be carried out to check the success of randomization through the two treatment conditions.
The primary efficacy analysis will use an intention-to-treat (ITT) base comparing the main outcome – EPDS – between arms in all the time points as a continuous variable. We will use a repeated measures (RM) design using linear mixed-effects regression models, including participants and the corresponding health center in the random part of the model, by means of the restricted maximum likelihood method (REML). Estimations of slope coefficients (and their 95% confidence intervals [CI]), adjusted for age, nulliparity, previous episodes of depression, and timing of receipt of intervention, will be calculated. To observe the specific trajectories through the study and to evaluate whether possible differences caused by the condition treatment are consistent over time, we will consider the “treatment × time” interaction. In parallel, a per-protocol analysis, with a minimum dose assumed to be ≥ 50% attendance , will also be carried out.
If missing data occur in the sample, multiple imputations by using chained equations to replace missing values will be calculated after ensuring data are missing at random (MAR), and as long as there are < 40% missing data in the corresponding variable to ensure validity of imputations . Cohen’s d statistic, as an effect size (ES) measure of group differences will be estimated by means of pooled pre-test SDs to weight for the differences in the pre–post means . Values of d = 0.20 are regarded as small, 0.50 as medium, and 0.80 large. Secondary analyses will comprise the PSS, PANAS, FFMQ, SCS, and EEP, and will use the same analytical strategy described above.
Cost-effectiveness and cost-utility procedures of analysis will also be conducted calculating incremental cost-effectiveness (ICER) and incremental cost-utility (ICUR) ratios. The effectiveness of the interventions will be estimated by means of the difference between the EPDS score at baseline and at follow-up; utility will be estimated using quality-adjusted life-year (QALYs) at follow-up. QALYs will be calculated using the area-under-the-curve (AUC). In addition, cost-utility planes will be plotted.
The overall alpha level will be set at 0.05 using two-sided tests and considering Benjamini–Hochberg’s correction for the primary outcome analyses as a way to balance between errors. However, no corrections will be made for secondary outcome analyses.