Core outcomes for vasa previa identified

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Introduction

Patients who experienced vasa previa and health care professionals agree on core outcomes and vital elements that should drive future data, according to a recent study published in JAMA Network Open.¹

While only 0.46 in 1000 pregnancies are impacted by vasa previa, an estimated 40% to 60% of newborns will not survive if the condition is not diagnosed prior to labor.² This highlights the need for early screening and improved management plans, but investigators have reported a lack of high-quality evidence to develop diagnosis and treatment guidelines.¹

“One solution is to develop a core outcome set, a minimum set of outcomes considered important by families with lived experience of vasa previa (referred to as health service users [HSUs]) and health care professionals (HCPs),” wrote investigators.

Study methodology

To determine a consensus between HSUs and HCPs toward vasa previa diagnosis and treatment, investigators conducted a survey study. The study led to the development of the Core Outcome Set for Studies on Vasa Previa (COVasP) and was part of an international research group including members from multiple disciplines, perspectives, and expertise.

A systematic review and qualitative study were assessed to determine relevant outcomes. Eighteen HSUs and 6 HCPs were interviewed in the qualitative review to identify 53 patient-important outcomes and experience measures. Additionally, 74 outcomes were identified in the systematic review.

Sixty-seven outcomes were included in the core outcome step development. This process involved a 2-round online Delphi survey, small group discussions, and a final consensus meeting.

Survey process

Participants of the Delphi survey were recruited between March 14 and April 28, 2021, and were categorized as either HSUs or HCPs. Starting March 14, 2021, participants were given 6 weeks to complete the online survey. This included a demographic questionnaire including clinic specialty, country of residence, and countries of practice or birth.

The 5 core domains for outcomes include mortality, morbidity, life impact, resource use, and adverse events. The importance of outcomes was rated on a 9-point Likert scale, with scores of 1 to 3 considered not essential, 4 to 6 important but not critical, and 7 to 9 clinically important.

Participants were also able to select when they were unable to score an outcome and could suggest outcomes not included in the initial list. Clinical terms received lay explanation to ensure nonclinicians understood the questions.

If a new suggestion was considered unique by clinicians, it was included in the second survey. Outcomes with 70% scoring 7 to 9 points in the second survey were classified as consensus in, while those with 70% scoring 1 to 3 points were considered consensus out. The remainder were classified as no consensus.

Survey participation and findings

Two hundred and four individuals completed the first survey, 89 of whom were HCPs and 115 were HSUs. In this survey, 48 new outcomes were suggested, with 10 being included in the second survey after discussion by the COVasP study team. There were 130 participants in the second survey, 74 of whom were HCPs and 56 were HSUs.

Consensus in was reported for 33 outcomes after the second round, while consensus was not reached for 44. A consensus out rating was not reported for any outcomes. The number of items was further reduced by combining similar items such as miscarriage and stillbirth into fetal death.

Refinement of outcomes

Certain items were deemed important to study but not adhering to the definition of outcomes in clinical research and were classified as reporting checklist items. This led to 36 survey items being discussed during the small group discussions.

During the discussion, participants identified items such as the type of anesthesia or analgesia for birth that should be listed as reporting checklist items. Additionally, participants noted that many clinical units are unable to confirm the antenatal diagnosis of vasa previa on histopathology, making it restrictive to depend on histopathology alone.

All but 6 outcomes reached consensus, with these 6 outcomes discussed at a final meeting. There were 13 core items identified, 8 of which were fetal outcomes and 5 were maternal outcomes. Twenty-two reporting checklist items also reached consensus.

“These tools are available in fillable format aimed at standardizing outcome selection, incorporating patient-important outcomes into research, harmonizing data synthesis, and facilitating the development of patient-centered clinical guidelines for this rare, but potentially devastating condition,” wrote investigators.

References

1. Yeretsian T, Javid N, Hirschhorn-Edwards N, et al. Core outcome set and reporting checklist for studies on vasa previa. JAMA Netw Open. 2025;8(3):e251000. doi:10.1001/jamanetworkopen.2025.1000
2. Pavalagantharajah S, Villani LA, D'Souza R. Vasa previa and associated risk factors: a systematic review and meta-analysis. Am J Obstet Gynecol MFM. 2020;2(3):100117. doi:10.1016/j.ajogmf.2020.100117