BackgroundMaternal obesity is a risk factor for adverse maternal, fetal, and neonatal events. Numerous clinical trials are currently exploring the effectiveness of antenatal and peripartum interventions in improving pregnancy outcomes that can in future inform clinical practice. However, the heterogeneity in outcome reporting limits our ability to compare outcomes across studies, and there is a lack of stakeholder representation in outcome choice. A pragmatic solution to this problem is the development of a core outcome set (COS) that defines the minimum criteria for outcome reporting in clinical trials undertaken in this population, arrived at by the involvement of relevant stakeholders.MethodsThe development of a COS for studies on obesity in pregnant patients (COSSOPP) will comprise five steps. First, a systematic review of published literature will identify the long list of outcomes, their definitions and measurements if applicable, and outcome reporting quality. This will be followed by a meta-synthesis of qualitative studies with patients, and qualitative interviews in Toronto with patients, clinicians, researchers, hospital administrators, and policy-makers, to identify novel outcomes that were not obtained through systematic review. Third, the long list of outcomes will be narrowed down through online Delphi surveys involving an international group of patients and relevant stakeholders. This will be followed by a face-to-face consensus meeting with representatives of all stakeholder groups to arrive at a consensus on the final COS. Finally, in order to determine how the identified core outcomes should be measured, we will conduct another literature review and Delphi process.DiscussionCOSSOPP will engage patients, clinicians, researchers, and other relevant stakeholders in determining the core set of outcomes that should be reported and measured in order to harmonize outcome reporting in studies evaluating the effectiveness of antepartum and peripartum interventions in obese pregnant women. This protocol provides a detailed overview of the steps involved in the development of a COS, to guide researchers in developing COS within their areas of specialization.COMET Core Outcome Set Registrationhttp://www.comet-initiative.org/studies/details/939.Electronic supplementary materialThe online version of this article (10.1186/s13063-018-3029-1) contains supplementary material, which is available to authorized users.

Summary Although considerable research is being conducted with a view to improve outcomes for pregnant women with obesity and their babies, much of this research is compromised by the quality of outcome reporting. Our aim is to determine how outcomes have been reported and measured in obesity in pregnancy studies, as a first step towards developing a core outcome set to standardize outcome reporting in future trials. We conducted a systematic review of clinical trials and systematic reviews on obesity in pregnancy in accordance with the Preferred Reporting in Systematic Reviews and Meta‐analyses guidelines. We searched Medline, Embase, controlled register of trials, World Health Organization International Clinical Trials Registry, http://www.clinicaltrials.gov and Google Scholar, for relevant studies and extracted study characteristics, outcome reporting and measurement. Reporting quality was assessed using previously published criteria. Outcomes were grouped using a published taxonomy and variations in outcome reporting and measurement were descriptively presented. Seventy included studies yielded a total of 135 outcomes. Foetal/neonatal outcomes were not reported in 53.3% of studies where an intervention could have implications to both, mother and baby. Reported outcomes were mostly physiological/clinical (74.8%), with very limited representation of outcomes related to mortality/survival (5.2%), life impact (7.4%), adverse events (5.9%) and resource utilization (6.7%).

INTRODUCTION: Improving outcomes in women with obesity (BMI>30 kg/m2) in pregnancy is limited by the heterogeneous outcomes between clinical trials. This systematic review of antepartum and peripartum interventions/exposures aimed to determine outcomes and their definitions reported thus far, as a preliminary step towards the standardization of outcomes. METHODS: MEDLINE, Embase, CENTRAL and www.clinicalTrials.gov were searched for trials, secondary analyses and systematic reviews in English between 01 January 2000 and 20 November 2017. Grey literature and reference lists of included studies were searched. Title/abstracts and full-texts were screened in duplicate. The following data were extracted: study characteristics, primary, secondary maternal, fetal and neonatal outcomes (including composites), their definitions or measurements and outcome reporting quality (MOMENT criteria). The proportion of studies reporting each outcome, a primary outcome and variations in definitions and components of composite outcomes were determined. RESULTS: Of 4916 results screened, 218 full-texts were assessed and 70 included. 173 maternal/obstetric outcomes and 86 neonatal/fetal outcomes were reported. 49 of the 58 trials/registrations reported a primary outcome, 21 of which were not in a reproducible way. The most frequent maternal outcome was gestational weight gain (24 studies) with inconsistent definitions between studies. The most frequent fetal/neonatal outcome was birthweight (17 studies). There were three maternal composite outcomes, one fetal/neonatal and one combined. No maternal composite comprised the same components. CONCLUSION: The high number of outcomes prevents the reporting of relevant outcomes in all obesity in pregnancy studies. Further, inconsistencies and variations between outcome choices and definitions identified present challenges for study comparability and data aggregation.