Funding
This article is adapted from a report undertaken by the SBU, who provided funding for the study.
Keywords: Childbirth, Core outcome set, Maternal health, Obstetric care, Pregnancy

Tweetable abstract

A systematic review of completed and ongoing Core Outcomes Sets (COS) relating to pregnancy and childbirth by @SBU_en

Introduction

Well- designed and well conducted randomized controlled trials (RCTs) determine the effectiveness of different interventions through unbiased comparison of outcomes (events or endpoints). The selection of outcomes is critical in RCT design, and trials may be regarded as “only as credible as their outcomes”. However, outcomes may be defined in various ways, resulting in the reporting of multiple, apparently different outcomes across studies. This has a negative impact on evidence synthesis, contributing to heterogeneity and research waste (1-3).
To overcome these problems, the selection of outcomes and measurement properties in studies need to be standardised. Described and promoted by the Core Outcome Measures in Effectiveness Trials (COMET) initiative group in 2010, Core Outcome Sets (COS) have increasingly been developed for various conditions over time (2). A COS is a minimum set of outcomes to be selected, measured, and reported in trials of a specific condition. These are typically developed by identifying and describing the outcomes used in current research (primary studies as well as systematic reviews) and then allowing stakeholders to prioritize these outcomes by using a consensus process. When a core outcome set has been agreed on, the purpose is that researchers use it in all studies within that condition, adding further outcomes if they wish (Figure 1). The aim of developing and implementing COS is that the results of various studies will be more readily comparable and collated, reinforcing the basis of decisions, to benefit patients and healthcare personnel.
In the research fields of women’s health and neonatal health, an international network, called CoRe Outcomes in Women’s and Newborn health (CROWN), has been established (4). It is led by journal editors, and aims to address the widespread, unwarranted variation in reporting of outcomes, which makes comparison between and combination of results across studies difficult, if not impossible.
The aim of this article was to systematically identify and describe ongoing and completed studies prioritizing outcomes within the field of pregnancy and childbirth.

Methods

The study consisted of a systematic literature review undertaken to analyse and summarize ongoing and completed COS projects (including all projects where outcomes where prioritized), within the area of obstetric care. The literature search was conducted in June 2019. However, the search of the COMET Initiative database was updated in January 2020.

Protocol and registration

A project plan was established a priori and registered at SBU, the PROSPERO database (5) as well as the COMET database (6). This systematic review was conducted and reported in accordance with the PRISMA statement.

Eligibility criteria

The criteria for eligibility were outlined according to the PICOS model (Population, Intervention, Comparator, Outcome and Study design) and included the following characteristics:
Population: Pregnant women, women giving birth (labour and delivery), women who suffer an injury or other complication related to childbirth, women or men suffering from a mental health disorder during pregnancy or during or after childbirth.
Intervention: No restriction.
Control: Not applicable.
Outcome: A list of outcomes included in the COS.
Study design: Ongoing or completed original studies where outcomes were prioritized using some form of consensus. No restriction applied to publication status.
Language: English and Scandinavian languages.