Table 1 Inclusion and exclusion criteria

• Written in English

• Published, peer reviewed article

• Reports primary data

• Randomised controlled trial, controlled trial, observational study with a control group/condition, before and after study

• Reports quantitative data on effectiveness of an intervention

• Participants are pregnant women or women planning pregnancy

• Intervention aims to increase adherence to prescribed medication for a chronic condition or pregnancy-related indication (e.g. pre-eclampsia risk)

• Reports at least one of: perinatal, maternal clinical (< 6 weeks postnatal), objective or self-reported adherence to medication during pregnancy

• Not in English

• Not a published, peer reviewed article

• Not a full text article e.g. conference abstract, i.e. unlikely to provide adequate information to extract methodological and outcome data.

• Does not report primary data (e.g. review, commentary, editorial), such that it does not give adequate data to assess of intervention effects on outcomes of interest.

• Trial registration or protocol, i.e. no data available about study results

• Effectiveness of an intervention not assessed e.g. descriptive study or qualitative assessment.

• Studies without a control group or control timepoint.

• Trial or observational study of an intervention with only one participant (e.g. case reports), thus are of limited validity due to high risk of bias

• Does not report data about pregnant women or pre-conceptual women; reports data including both pregnant and non-pregnant sample that is not disaggregated.

• Intervention does not aim to address medication adherence (e.g. addresses adherence to other parts of self-management such as blood glucose monitoring, physiotherapy)

• Does not report at least one of perinatal, maternal clinical, objective or self-reported adherence outcomes during pregnancy

• Trial ended or data withdrawn, thus data should not be included in review.

• Trial aims to address medication adherence to opioid addiction treatment Opioid addiction adherence interventions may not be relevant to women with chronic conditions and pregnancy-related indications.

• Trial aims to assess medication adherence to treatment in pregnant women with mental health conditions or smoking cessation. These studies are not relevant to the research objectives.

• Trial aims to address adherence to iron supplementation for anaemia only- there is no clear evidence that adherence to medication for anaemia improves clinical outcomes.

• Self-reported or objective adherence is not assessed during pregnancy.

• Clinical outcomes are measured > 6 weeks postnatally and therefore is unlikely to reflect adherence during the pregnancy.