Prioritisation of early pregnancy risk factors for stillbirth: An international multistakeholder modified e-Delphi consensus study

Objective

To identify and prioritise early pregnancy risk factors for stillbirth to inform prognostic factor and model research.

Study design

We used a modified e-Delphi method and consultation meeting to achieve consensus. Risk factors for early, late and stillbirth at any gestation identified from an umbrella review of risk factors for stillbirth were entered into a two-stage online Delphi survey with an international group of stakeholders made up of healthcare professionals and researchers.

The RAND/ University of California at Los Angeles appropriateness method was used to evaluate consensus. Responders voted on a scale of 1–9 for each risk factor in terms of importance for early, late, and stillbirth at any gestation. Consensus for inclusion was reached if the median score was in the top tertile and at least two thirds of panellists had scored the risk factor within the top tertile.

Results

Twenty-six risk factors were identified from an umbrella review and presented to stakeholders in round 1 of our e-Delphi survey. Round 1 was completed by 68 stakeholders, 79% (54/68) of whom went on to complete the second round. Seventeen risk factors were discussed at the consensus meeting. From the twenty-six risk factors identified, fifteen of these were prioritised for stillbirth at any gestation, eleven for early stillbirth, and sixteen for late stillbirth, across three domains of maternal characteristics, ultrasound markers and biochemical markers. The prioritised maternal characteristics common to early, late, and stillbirth at any gestation were: maternal age, smoking, drug misuse, history of heritable thrombophilia, hypertension, renal disease, diabetes, previous stillbirth and multiple pregnancy. Maternal BMI, access to healthcare, and socioeconomic status were prioritised for late stillbirth and stillbirth at any gestation. Previous pre-eclampsia and previous small for gestational age baby were prioritised for late stillbirth. Of the ultrasound markers, uterine artery Doppler pulsatility index and congenital fetal anomaly were prioritised for all. One biochemical marker, placental growth factor, was prioritised for stillbirth at any gestation.

Conclusions

Our prioritised risk factors for stillbirth can inform formal factor-outcome evaluation of early pregnancy risk factors to influence public health strategies on prevention of such risk factors to prevent stillbirth.