Validation of the demographic Fetal Medicine Foundation Risk Calculator
in predicting singleton antepartum stillbirth -- A retrospective
case-control study
Abstract
Objectives: To externally validate the demographic setting of the online
Fetal Medicine Foundation (FMF) Stillbirth Risk Calculator based upon
maternal medical and obstetric history in a case-matched cohort. Design:
Retrospective case-control study Setting: Tertiary referral hospital
Population: 144 fetuses after singleton intrauterine fetal death (IUFD)
and a matched control group of 247 singleton live births between 2003
and 2019 Methods: Nonparametric receiver operating characteristics (ROC)
analysis was performed to predict the prognostic power of the risk score
and to generate a cut-off value to discriminate best between the events
of stillbirth versus live birth. Main Outcome Measures: FMF Stillbirth
risk score Results: The IUFD cohort conveyed a significantly higher
overall risk assessment with a median FMF Stillbirth risk score of
0.45% (0.19-5.70%) compared to live births [0.23% (0.18-1.30%);
p<0.001]. Demographic factors mainly contributing to the
increased risk were BMI (p=0.002), smoking (p<0.001), chronic
hypertension (p=0.015), APS (p=0.017), type 2 diabetes
(p<0.001) and need for insulin (p<0.001). ROC
analysis to evaluate the discriminative ability of the FMF Stillbirth
Risk Calculator showed an area under the curve (AUC) of 0.72 (95% CI
0.67–0.78; p<0.001). The FMF Stillbirth risk score at a
cut-off level of 0.34% (OR 6.22; 95% CI 3.91–9.89; p<0.001)
yielded a specificity of 82% and a sensitivity of 58% in predicting
singleton antepartum stillbirths. Conclusion: The FMF Stillbirth Risk
Calculator achieved a similar performance in our cohort of women as in
the reference group.