In Turkey, the prevalence rate of perinatal depression has been estimated between 20%-40%, reflecting the global average of 25%. Untreated perinatal depression is of concern not only because of its effect on maternal health but also from the effect that impaired maternal role fulfilment has on the mother-infant bonding and child care and the long-term impact on the infant's physical and cognitive development. Thinking Healthy Programme (THP) is an evidence-based intervention incorporated into the World Health Organization's flagship Mental Health Gap Action Programme, tailored to the perinatal period that has been shown to be effective for depressed or stressed mothers. Turkey prioritize antenatal care, and this provides an opportunity to integrate mental health care into an existing antenatal care programme. Public hospitals operate 'antenatal pregnancy schools' where women are invited to attend 5 weekly group sessions that incorporate education about pregnancy and newborn care. We have developed an on-line group version of the Thinking Healthy Programme which has been designed to be integrated into the routine on-line antenatal pregnancy classes. The intervention has been designed so it is suitable for all women (universal) rather than depressed mothers only (targeted).

The aim of this study is to pilot this adapted on-line group intervention in selected hospitals' pregnancy schools.

The study will be a two-arm pilot individual randomised controlled trial comparing the Thinking Healthy group intervention integrated into antenatal pregnancy school classes with antenatal pregnancy school classes alone. Our sample size of 60 pregnant women (that is 30 participants in each arm of the pilot trial), who are over 18 years old, between 12-30 weeks' gestation, and intend to attend all 5 sessions of the online antenatal classes. Participants in both arms will be assessed for depression and anxiety symptoms, levels of disability, quality of sleep, perceived social support, coping skills, and relationship with partner. All one hundred and twenty women will get a detailed assessment initially and 4-6 weeks after the intervention. Some of the study participants and antenatal nurses delivering these sessions will be approached for in-depth qualitative interviews to explore the acceptability, feasibility and perceptions of the study participants' receiving the intervention sessions.

Systematic reviews provide robust evidence that perinatal depression can be treated effectively in low to middle income countries with psychological treatments delivered by non-specialists. The intervention with the strongest demonstrated effect size is the Thinking Healthy Programme, the first psychological intervention to be incorporated into the World Health Organization's flagship Mental Health Gap Action Programme (mhGAP). Turkey prioritize antenatal care, and this provides an opportunity to integrate mental health care into an existing antenatal care programme.

Public hospitals operate 'antenatal pregnancy schools' where women are invited to attend 5 weekly group sessions that incorporate education about pregnancy and newborn care. The groups usually consist of 8-10 mothers and are run by antenatal nurses. During the COVID19 pandemic, these classes have been adapted into an on-line platform. Group interventions are less resource-intensive per person helped than individual interventions and are possibly more cost-effective. We have developed an on-line group version of the Thinking Healthy Programme which has been designed to be integrated into the routine on-line antenatal pregnancy classes. The intervention has been designed so it is suitable for all women (universal) rather than depressed mothers only (targeted).

Our objectives are to conduct a pilot/feasibility study of the on-line group intervention in a socioeconomically deprived population in Istanbul, Turkey.

The primary aim of this pilot study is not to test a specific hypothesis but to:

1. test all operational elements including: the acceptability and feasibility of the intervention including training and supervision; the materials developed such as the manual, visual aids, and added activities to promote perinatal mental health and psychosocial well-being;
2. test the willingness of women, and antenatal nurses to participate (recruitment rates), respond to questionnaires, and be followed up (attrition rates); and
3. test the procedures for outcome measures as well as training and supervision. Quantitative methods will closely follow the procedures for a future definitive trial. The results will be used to finalise the intervention content and structure, to establish appropriate support systems, and to finalize all materials.

The study will be conducted in socioeconomically deprived districts of Istanbul within the catchment area of the First Region of the Public Hospitals Union. Primary institution will be Marmara University Hospital which has an affiliation with the Ministry of Health. With the support of Turkish Ministry of Health, the hospital operates 'antenatal pregnancy schools'.

Our study participants will include all consecutive pregnant women who have been offered, and accepted to attend, the on-line antenatal care classes during the study recruitment period.

Because this is a feasibility/pilot trial, sample size calculations have not been conducted. Our sample size of 60 (that is 30 participants in each arm of the pilot trial) is based on the pragmatics of recruitment and the necessities for examining feasibility. The intervention and control arms will each consist of 3 groups per arm with 10 participants per group, respectively.

The research design is a two-arm pilot individual randomised controlled trial comparing the Thinking Healthy group intervention integrated into antenatal health classes with antenatal health classes alone.The unit of randomization for the pilot trial will be individuals (i.e, eligible pregnant women). The generation of random allocation sequence will be carried-out by an independent person at the University of Liverpool UK (not involved in the enrolment of participants into the trial). Simple random numbers will be generated and the case will be assigned a Trial Number and treatment allocation (TAU or THP) which will be emailed back to the Local PI at Marmara in an encrypted form who will be responsible for notifying the site coordinator. The site coordinator will then inform both the participants and the designated nurses for the particular treatments to commence. To minimise the threat of selection bias through allocation concealment, the team recruiting/enrolling participants will be separate to the team opening the encrypted forms and informing participants about the treatment that will receive.

The main outcomes will be recorded by outcome assessors blinded to treatment allocation. Participants will be asked before the interview with the assessor not to reveal anything about their sessions. The outcome assessors will not have information about the on-line groups. It will not be possible to blind therapists and antenatal nurses in participating centres or the participants themselves to intervention allocation.

Intervention The Thinking Healthy Programme (THP) is an evidence-based intervention that is based on principles of cognitive behavioral therapy. It includes strategies that incorporate behavioral activation, active listening, collaboration with the family, guided discovery, and homework. THP was designed to be delivered by community health workers, and it was the first low-intensity psychological intervention to be adopted by WHO. THP has been translated and adapted into Turkish. For the current study, we have developed an on-line group version of the Thinking Healthy Programme which has been designed to be integrated into the routine on-line antenatal pregnancy classes. It will be delivered by trained antenatal nurses who routinely run the antenatal classes. The routine on-line antenatal classes consist of 5 weekly group sessions that incorporate education about pregnancy and new-born care. The groups usually consist of 8-10 mothers. Our adapted 'group' version of the Thinking Healthy Programme will be incorporated into these antenatal pregnancy classes. The adapted THP consists of 5 integrated sessions. Session 1 introduces the programme and focuses on engagement of participants, introduction of THP, and breathing exercises. Session 2 focuses on psychoeducation and problem solving. Session 3 focuses on the mother's well-being and introduces activities such as physical exercises, good sleep practices and ensuring a balanced diet. Session 4 focuses on the mother's relationship with the unborn baby. Session 5 focuses on activating social support from family, friends and peers and provides closure of therapy.

Participants randomized to the control arm will not be offered the THP intervention but will attend the 5 sessions of the routine group antenatal class. The class provides education about pregnancy, birth and new-born care and offers support to women. The women will also be able to access all usual care and support offered by the participating hospitals.

Assessments will take place at baseline on recruitment and one month after conclusion of the intervention sessions.

Procedures for human subjects' protection in this research will follow guidelines and policies of the Institutional Reviews Boards (IRBs) of the sponsoring organization, the University of Liverpool and the implementing partner, University of Marmara, School of Medicine.

The data and safety monitoring plan will involve the continuous evaluation of safety, data quality and data timeliness. Incoming data will be cleaned and compiled on a regular basis and examined for unusual or unexpected patterns. PIs and project coordinators will conduct continuous review of data and participant safety at monthly Project Management Group meetings and the discussion will be documented in minutes. The governance mechanisms will provide oversight to the programme. The governance and administrative activities will be based in Istanbul at Marmara University (School of Medicine) and will be the responsibility of the site investigators.

Flow of participants through the trial will be presented as the trial flow chart. Descriptive statistics including socio-demographic characteristics and all baseline measures across arms will be tabulated to check for any baseline imbalances among the participants. Mean and standard deviation scores for all continuous measures shall be presented, followed by univariate associations between demographic variables and severity of symptoms. While the study is not powered to test any hypothesis, exploratory intention to treat analysis will be conducted to compare the two treatment groups. For baseline comparisons, t-tests will be conducted for continuous variables and chi-squared test for categorical ones. At follow up, comparisons will be made using analysis of covariance with baseline score as a co-variate. Any significant baseline imbalances will be treated as co-variates and adjusted for in analysis. All qualitative data will be analysed using framework analysis approach

Inclusion Criteria:

• pregnant women over 18 years between 12-30 weeks' gestation have access to internet, intend to attend all 5 sessions of the antenatal classes

Exclusion Criteria:

• currently receiving any form of counselling or mental health care, who report suicidal ideation women who have a miscarriage, stillbirth or preterm birth will also be excluded from the follow-up assessment

pregnant women between 12-30 weeks' gestation

Requests for wider sharing of data (for example in response to information on the UoL, Marmara University webpages and in publications about the study and willingness to share), will be addressed on a case-by-case basis.

when data is ready for analysis

Any data sharing request will be made to investigators through a pre-defined data requisition form. This form will contain information about the applicant, institution, purpose of data request, study objectives, ethical clearance of the study, etc. Once a request has been made the data governance body will discuss if that request was appropriate and meets the criteria set by the participating centres; data will be released following signing of the data sharing agreement. The data will be stored on the Marmara University and UoL servers and not be deposited in any 'community' database.

The main outcomes will be recorded by outcome assessors blinded to treatment allocation. It will not be possible to blind antenatal nurses delivering the intervention in participating centres or the participants themselves to intervention allocation.