Participants

The HELP 24m study aimed to follow-up women who participated in the HELP trial, and their children born during participation in this trial, at 24 months postpartum. A total of 598 women were recruited to the HELP trial; 63 of these women had withdrawn by 12 months postpartum and were not eligible to be approached for follow-up. The study aimed to recruit and follow-up the remaining 535 (Intervention: 259, Control: 276) eligible women. Details on the flow of participants in the HELP trial introduced in this section, are provided in Chapter 4 (section 4.2)

Women had not consented to take part beyond 12 months postpartum in the HELP trial. Additionally, the HELP 24m study was considered a new study by the ethics committee rather than an amendment to the HELP trial protocol, therefore contact details could not be

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obtained for these women. To enable women to be recruited to the HELP 24m study, the following two stage process was used:

1) During the HELP trial women were asked to provide written agreement to be contacted about any future research related to the trial.

2) At 24 months postpartum, women who had provided this written agreement were approached and asked to consent to participate in the HELP 24m study.

3.3.1 Participant retention during the HELP trial

The work described here is documented in the HELP trial protocol, but it was an essential step in the set-up of the HELP 24m study and is therefore detailed.

Prior to completion of the HELP trial, and in anticipation of the start of the HELP 24m study, an amendment was made to the trial protocol to add a process for asking women to provide written agreement for retention of their contact details and future contact regarding related research studies, by the trial team. It was made clear to women that they were not agreeing to take part in any studies but only to receive communications regarding such studies. A database of participant contact details, held on CU servers, was created to support participant retention.(340, 341)

Women were either invited to provide this written agreement by the local researchers during the 12 months postpartum follow-up appointment, or they were subsequently contacted by the trial team. Maximum efforts were made to obtain written agreement from all 535 participants enrolled at 12 months postpartum, in order to reduce loss to follow-up and the chance of systematic differences in participants or lack of statistical power in the HELP 24m study. These efforts are described below.

Retention strategies were employed and adapted by the trial team on a participant by participant basis. That is, where one method failed, a decision was made on how to proceed for that individual, rather than a general approach which would have led to repeated failed contacts.(342) HELP trial participants who had not yet agreed to, nor declined the retention of their contact details, were approached initially via telephone if contact details were available, as this was expected to be a more effective method of contact in comparison to postal communication,(343) in addition to a more timely method given the immediate result of contact attempts. If participants agreed to retention of their contact details, a form to capture written agreement and updated details was posted, and women were asked to

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return this completed form in an enclosed prepaid envelope. For those that were not contactable by telephone, an invitation letter was posted to them along with the form. Where one method of contact was unsuccessful, the trial team attempted to use any other available details, which may have included post to home address, landline and mobile calls, SMS, email, or contact to a designated person (usually a relative) as provided by the participant at recruitment. A minimum of three attempts was made to each available contact method, on different days, and at different times of day. Where a contact detail was invalid and could not be used, it was not attempted again. Where the participant had agreed to provide their details via telephone but had not returned their form, they were contacted again, by telephone and post as appropriate, and given the opportunity to agree or decline. If no valid contact details appeared to be available for a participant, CTR administrators attempted to use publicly available registers, for example the electoral roll, to obtain contact details.

A database of contact attempts and outcomes was retained and continuously reviewed by the trial team, and a case by case decision was made as to when to cease contact attempts. The aim was to allow as many participants as possible the opportunity to be involved in future studies and to increase the value of such research, but to ensure that harassment of participants did not occur. During contacts it was made clear to women that they were under no obligation to provide agreement and could decline at any time, in which case no further contact attempts were made. Efforts to obtain agreement to retain details were prioritised by the date women reached the 24 months postpartum time point, and by sites where lower levels of agreement had been obtained, to try to reduce any imbalance between trial groups or clusters in any future study. The student assisted in participant retention efforts in the HELP trial. Results of these efforts are outlined in Chapter 4 (section 4.2.2).

3.3.2 Inclusion criteria for the HELP 24m quantitative phase

Women, and their children, were invited to take part in this study if they:

 had participated in the HELP trial, without withdrawal, inclusive of those that undertook both intervention and control group conditions;

 had provided written agreement to be contacted regarding future research.

3.3.3 Exclusion criteria for the HELP 24m quantitative phase

The study did not seek to exclude women on any other criteria. There were potential scenarios that would require amendment of these exclusion conditions. If a child had been taken into care, follow-up data for the mother would be collected, but no child outcomes

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would be assessed. If the mother had died, no attempt would be made to collect data for the child. In the case of child death, women would be given the option to participate, and only maternal outcomes would be assessed. If a woman consented to take part but preferred for her child not to; or if the child was not available or unwilling to take part, then only maternal outcomes and parent-reported child outcomes would be assessed, other child measures were recorded as missing.

3.3.4 Recruitment procedure and informed consent

The local researcher was contacted via email by the student, three weeks before an individual meeting the inclusion criteria (section 3.3.2) reached the 24 months postpartum time point. The local researcher was asked to make contact with the woman via telephone, email or post, to invite her to take part in the HELP 24m follow-up. On initial contact, the local researcher provided a brief description of the study, and for those women interested in taking part, an appointment was made for follow-up at a time and place convenient to them, usually their home. An appointment letter (Appendix D) and participant information sheet (Appendix E), was then posted to the woman.

Women to be recruited by the student were contacted by CTR administration staff via telephone and provided with information about the study. For those women who agreed to take part, appointments were arranged for the student to conduct visits, and the same information was then posted to these women. The day before arranged appointments, the student made contact with women by SMS or telephone, to confirm arrangements.

During visits, women were given time to read the information sheet and to ask questions. Women were reminded during all contacts and visits that they were free to decline their own or their child’s participation and retained the right to withdraw consent for participation in any aspect of the study without their care, or the care of their child, being affected. If a woman agreed to her and her child taking part, she was asked to provide written consent (Appendix F). The local researcher, or student, then proceeded to collect the follow-up data. A screening log (Appendix G) was retained to record details of women who declined to take part in the study, and at what stage they declined.

Every effort was made to reduce loss to follow-up in order to avoid bias in the sample recruited to the study. Women could choose a convenient setting for the visit which aimed to improve response rates.(341) They were also given a £10 voucher as a thank you for taking part and to encourage participant retention.(344) Steps followed during recruitment aimed to

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ensure that all eligible women were invited to take part, and these steps are described below.

Attempts to contact eligible women were made using any valid method available. If local researchers had not had successful contact with an individual five days before their 24 months postpartum date was reached, they were to inform the student. CTR administrators then attempted to contact the individual using any available details, which may have included post to home address, landline and mobile calls, SMS, email, or contact to a designated person. A minimum of three attempts was made to each available contact method on different days and at different times of day, provided the method of contact appeared to be valid. A database of contact attempts and outcomes was retained and continuously reviewed, to manage efforts but also to monitor loss to follow-up and to record the associated reasons. If CTR administrators successfully contacted an individual and they were willing to take part, a visit from the student was arranged, or it was referred back to the local researcher to arrange an appointment, as appropriate.