Pregnancy Nutrition Core Outcome Set (PRENCOS): A core outcome set development study

Objective: To develop a core outcome set for pregnancy nutrition. Design: Mixed-methods core outcome set development study. Setting: Online. Population: Healthcare professionals, researchers and women with experience of pregnancy. Methods: Candidate outcomes were identified from a systematic review of intervention and observational studies. One-to-one semi-structured interviews with women with experience of pregnancy (n = 26) were transcribed and analysed using inductive thematic analysis. Outcomes were consolidated, organised into domains and categorised using the Core Outcome Measures in Effectiveness Trials taxonomy. A two-round, modified Delphi survey (May-August 2021) was conducted. Participants voted on how critical each outcome was to include using a nine-point Likert scale. All outcomes that did not reach consensus were discussed at a consensus meeting. Main outcome measures: Critical outcomes to include in the core outcome set. Results: A total of 53 091 articles were identified. Outcomes were extracted from 427 articles. The qualitative data yielded 45 outcomes. An additional 24 outcomes came from the literature. In round one, 82 participants ranked 30 outcomes. One new outcome was included in round two, during which participants (n = 60) voted 12/31 outcomes as critical to include. The remaining 20 outcomes were discussed at the consensus meeting and two outcomes were included. Maternal outcomes included: pregnancy complications; delivery complications; maternal wellbeing; gestational weight change; maternal vitamin and mineral status; mental health; diet quality; nutritional intakes; need for treatments, interventions, medications and supplements; pregnancy loss or perinatal death; birth defects or congenital anomalies; neonatal complications; and newborn anthropometry and body composition. Conclusions: The use of the Pregnancy Nutrition Core Outcome Set (PRENCOS) will ensure researchers measure what matters most from the perspective of key stakeholders.