The effects and process of the intervention “Individual Shantala Infant Massage” in preventive child healthcare to improve parent–child interaction: study protocol for a quasi-experimental study

The Netherlands has a solid Preventive Child Healthcare (PCH) system to promote health, prevent diseases, and enable early identification of problems in the physical, psychological, social and cognitive domains in children. Basic preventive care is provided to all children aged 0–18 years, including periodic health check-ups, vaccinations, screening, and advice e.g., on safety, lifestyle, and parenting. All PCH services are provided free of charge and they have an outreach of up to 95% [17]. In addition to the basic PCH services, selective preventive care can be provided to children who grow up in disadvantaged situations, including the deployment of interventions [18]. In order to maintain the quality of interventions and to foster the implementation of effective interventions, the National Institute for Public Health and the Environment (in Dutch: Rijksinstituut voor Volksgezondheid en Milieu; RIVM) of the Ministry of Health, Welfare and Sport runs a national database of interventions. For an intervention to be registered in this database, a clear protocol and a theoretical scientific base need to be provided and be evaluated by an independent committee of experts. Depending on the amount of evidence from effect evaluations, interventions can be rated on various levels of effectiveness, ranging from ‘theoretically well-founded’ to ‘proven to be effective’ [19]. Currently, the range of interventions in this database supporting vulnerable parents to enhance positive, sensitive, responsive parenting in the first 1000 days is rather limited [20]. This holds particularly for broad, preventive, and accessible interventions.

A promising accessible and preventive intervention targeting parenting and stress in vulnerable parents is “Individual Shantala Infant Massage” (in Dutch: “Shantala babymassage individueel”), which is currently registered in the intervention database as ‘theoretically well founded’ [21]. This intervention is intended for parents with a baby from 6 weeks to 9 months of age, with a risk of low sensitive parenting behavior and/or (eventually) a risk of attachment issues because of challenges or stress that parents experience, or circumstances that heighten the risk of parent–child interaction problems such as excessive infant crying. Participation in the intervention is voluntary and without costs for the parent. The infant massage intervention can be offered to all caregivers, but participants are primarily mothers. The intervention is carried out as part of PCH services by a certified nurse. During three home visits, the nurse teaches a parent how to massage their infant and simultaneously provides parenting support.

The ultimate goal of the intervention is to foster a secure attachment relationship between parent and child by 1) increasing parental sensitive responsiveness, 2) increasing parenting confidence, and 3) reducing (effects of) stress, by improving stress coping and reducing experienced parenting stress of the parent, reducing stress and fussiness in the infant and reducing physiological stress in both the parent and the infant. The goals of the intervention are presented in Fig. 1.

Effects of infant massage have been studied before, on a wide range of outcomes. In premature infants, infant massage has been associated with shorter hospital stays, better infant growth and health, as well as reduced parent anxiety, depression and stress [22, 23]). Positive outcomes have also been reported in full-term healthy babies, including growth, intestinal cramps, diarrhea, bilirubin levels, stress hormones, sleep, crying and (motor) development [24‐26].

Infant massage is also supposed to promote positive parent–child interaction, because the parent learns to recognize signals better, reacts sensitively and makes eye contact e.g. [27]. Oxytocin, a hormone released in parent and child during physical contact, is thought to play an important role in this process. That is, oxytocin can counteract the physiological response to stress, reduce anxiety and increase social responsiveness, and is related to (sensitive) parenting behavior, affective touch, eye contact, communication and the emotional bond between parent and child (e.g. [25, 28‐30]. Positive effects of infant massage indeed have been found on parent–child interaction (e.g., [25, 26, 31], and on attitudes about parenting, parenting competence, and parenting stress of parents [32, 33].

Despite these promising results, the evidence base is still limited. In some studies there is a high risk of bias [24, 25]. Moreover, reviews and meta-analyses point to the large variation in effect studies when it comes to techniques, form, duration, frequency and performer of infant massage, choice and rationale of outcome measures, target population and quality of research e.g. [22, 24, 25]. Consequently, results are not always unequivocal.

Research on infant massage programs to promote the parent–child relationship also showed that effects can depend on content as well as the target population [34, 35]. Based on theory, research, observations, and interviews, 14 elements were identified that are potentially important for a successful approach. Examples of these are: the facilitator (e.g. a regular professional throughout intervention sessions, who has personal and technical skills); education on infant signals, demonstration on a doll, a safe atmosphere, meeting (physical) needs of participants, social interaction, and group size. An evaluation of eight infant massage programs found large differences in the extent to which these mechanisms were applied. The conclusion of this study was that infant massage programs, if of good quality, can be used particularly effectively for parents with moderate problems [35]. Although these findings highlight the need for additional research to gain more insight into the effects of infant massage, underlying mechanisms, and the possibilities to use infant massage as an intervention, infant massage is proposed as a relatively inexpensive, theoretically plausible and easily applicable method in care [35].

Several of the elements that have been identified as important for effectiveness in infant massage interventions to improve the parent-infant interaction [34, 35] are present in the intervention Individual Shantala Infant Massage. These include: parenting support with information on infant signals, intervention provided by an experienced nurse, skilled in teaching infant massage and sensitive parenting (with a doll), offering a personalized approach, a safe environment and connection to the (physical) needs of the parent. Next to massage instructions, the intervening youth nurse provides parenting support by discussing various themes with the parent, including the pace of the infant, crying, body language and basic communication. In practice, it often proves difficult for professionals to discuss sensitivity [36]. Infant massage offers a good entry point. The parent becomes more aware of the importance of eye contact and the signals of the infant, learns how to recognize these and how to respond in a sensitive responsive manner. Because the intervention is one-on-one, it is possible to adapt to individual needs, preferences and questions of parents. It is expected that in the safe, informal atmosphere of a home visit, the parent is more likely to share questions and concerns about the child and the personal situation. Because the intervening professional is a youth nurse, she has the necessary knowledge and skills to offer parents optimal support. As a result, parents' sense of parenting competence may be enhanced, parenting stress and worries can be reduced, and parents may learn to cope better with stress. This can contribute positively to the parent–child relationship [37]. This assumption is confirmed by experiences from PCH professionals and participating parents (Meijer, D: Procesevaluatie Shantala Babymassage Individueel, CJG Rijnmond, unpublished), (Van Delft I. & Zunderman H: Procesevaluatie Shantala Babymassage Individueel, CJG Rijnmond, unpublished) and by qualitative research on a similar intervention in Norway [32].

Individual Shantala Infant Massage is offered to parents with moderate problems, who experience stress in child-raising, caring for the baby or parenting, or have an increased risk of these forms of stress or problems interacting with the baby. The embedding in PCH services facilitates initial contact with the target group. As 95% of parents of young children are in regular contact with PCH [18], professionals have insight into which families are vulnerable and provide additional support accordingly. Additionally, the format of the intervention, with the practical infant massage containing non-lingual elements with an active role for the parent, makes it accessible and deployable for a wide target group, including people from a low socioeconomic background or people with language barriers. With three home visits, it is a short-term intervention making it less intensive compared to longer interventions. Interventions with up to five sessions have been shown to be as effective in increasing parental sensitivity as interventions with five to sixteen sessions [38].

The feasibility and promise of the intervention is supported by process evaluations of a PCH organization that provides this intervention as preventive support (Meijer, D: Procesevaluatie Shantala Babymassage Individueel, CJG Rijnmond, unpublished), (Van Delft I. & Zunderman H: Procesevaluatie Shantala Babymassage Individueel, CJG Rijnmond, unpublished). PCH professionals consider infant massage a feasible intervention that is highly appreciated as a tool for helping vulnerable families and their infants. Participating parents indicated that they learned the infant massage techniques but that they also learned to better recognize the signals of their infant, felt more supported in dealing with their infant, that the contact with their infant had improved and that their infant cried less.

Taken together, the intervention Individual Shantala Infant Massage could be a promising answer to the demand for easily accessible interventions to support vulnerable families during infancy.

Although the intervention is theoretically well-founded and evaluations from participating parents and professionals are promising, no controlled impact study has yet been conducted to study the effects of this intervention. Therefore, the aim of this quasi-experimental study is to investigate the effectiveness as well as the process of the Individual Shantala Infant Massage intervention as carried out in PCH.

The study has a quasi-experimental design. It is a non-randomized trial, carried out in the setting of PCH. A comparison is made between an intervention group and a control group: the intervention group consists of parent-infant dyads who receive the intervention Shantala Infant Massage as part of the care offered by their PCH organization. The control group consists of parent-infant dyads whose PCH organization does not offer this intervention as part of their standard care. Participant recruitment started in August 2021 and will end mid-2023. Data collection will continue until the end of 2023.

Prior to acceptance, the relevance and quality of the grant application were peer-reviewed by a team of (external) experts of the grant provider ZonMw. The Research Ethics Committee of the Radboud University Medical Centre in Nijmegen, The Netherlands (CMO region Arnhem-Nijmegen) judged this study not to be subject to the Medical Research Involving Human Subjects Act (in the Netherlands known by the Dutch abbreviation WMO, in full “Wet Medisch-wetenschappelijk Onderzoek met mensen), file number 2021–8221. The internal independent review board of TNO reviewed and approved the study’s compliance with laws and regulations concerning privacy sensitive data, reference number 2021–054. The study is conducted in accordance with guidelines and regulations of the Declaration of Helsinki. Prior to participation, all participants will receive information about the study and will provide informed consent. The study is registered in the ISRCTN registry, reference number ISRCTN16929184 [39]. Any substantial modifications to the protocol will be reported to ZonMw, the CMO, the internal review board of TNO and the ISRCTN registry.

Parents in the intervention group all receive Individual Shantala Infant Massage. This preventive intervention is aimed at parents with a risk of low sensitive parenting behaviour and/or (eventually) a risk of attachment issues. Examples of signals thereof taken into account by PCH at the parent level are: depressive symptoms, single, very young, unrealistic views about parenting, adverse childhood experiences, mental challenges, difficulties with parenting, pregnancy or delivery. Examples of signals in the parent–child interaction are: struggles to cope with infant crying, difficulties to adapt to the infant’s temperament, inadequate touching behaviour or little affective body contact, little to no emotional support (comforting, encouraging, supporting), lack of talking to the infant, not taking the infant into account and a lack of structure. When PCH professionals (nurses or physicians) notice these signals during PCH contact moments through observation and based on the conversation with the parent, the parent can be offered enrolment in the intervention. The intervention is offered as part of selective preventive PCH services, in addition to regular care as usual (see below).

A detailed description of the Individual Shantala Infant Massage intervention is provided on the website of the Dutch registry of health interventions [21]. The intervention consists of three weekly home visits of one hour. In exceptional cases when circumstances call for it (to the judgment of the nurse), a fourth visit is possible. The intervention is carried out at the parent’s home in a quiet and warm room. The visits have a fixed structure. Each session, the parent learns to massage a different part of the infant’s body (e.g., arms and legs). The intervening professional (i.e., a nurse) demonstrates the infant massage techniques on a doll and the parent massages the infant. The emphasis in massaging is on following the pace of the infant and being fully attentive to the infant. The intervention focuses on sensitive responses of the parent to the emotional, physical and mental state and the needs of the infant. The nurse works on increasing parental sensitivity by alerting the parent to the infant's signals (by naming and interpreting them), by showing the parent how he/she can respond positively to these signals and by naming the infant's responses to the parent’s behaviours. The nurse also informs the parent about crying, body language and basic communication as standard part of the intervention. Other topics and questions of the parent can be discussed as well, depending on his or her needs. The nurse stimulates the parent to massage the infant a couple of times a week, in between the home visits and after completion of the intervention and provides advice on how the parent can achieve this. The parent receives an information sheet depicting the various massage techniques with written instructions.

After intervention completion, the parent is allowed to contact the nurse with questions if necessary. Participation in the intervention is registered in the PCH child file, so (other) PCH professionals can ask about it during subsequent contact moments. If it appears that follow-up action and/or additional care is required for the family, necessary steps will be undertaken.

All parents, both in the intervention and in the control group, receive the regular basic preventive care from their PCH organization including periodic health check-ups, the monitoring of growth and development, advice e.g. on safety, lifestyle and parenting, and possible referral to other services. Additionally, the intervention group receives the Individual Shantala Infant Massage intervention as part of selective preventive care provided by their PCH organization.

The study consists of three measurement moments: a pre-test (T0; at inclusion), a post-test (T1; post-intervention (intervention group) or approximately four weeks after T0 (control group), and follow-up (T2; when the child is 5 months old). Table 1 provides an overview of the various measurements at different timepoints.

Parents complete questionnaires at T0, T1, and T2. All questionnaires are administered digitally via a secure website by default, but participants can receive a paper version upon request. At T2, a tuft of hair is cut from the parents’ head for the assessment of hair cortisol levels. The hair is cut during the 5-month contact moment at the PCH organization or at home by a member of the research team, depending on the PCH organization. Data on infant growth and development from birth up to six months that are collected by PCH as part of standard care, will be obtained from the PCH files.

In the intervention group, additional data is collected for the purpose of process evaluation. Between T0 and T1, the nurses carrying out the intervention keep semi-structured logbooks of the intervention sessions. At T1, parents complete an extra evaluation questionnaire. Finally, interviews are conducted with a number of parents and professionals.