Bulgarian Federation of Obstetrics and Gynecology (BFOG) fetal weight charts

Introduction: Existing international fetal growth charts do not reflect specific characteristics of local populations. This study examines fetal growth and development in the Bulgarian population, with the primary goal of establishing local reference ranges for estimated fetal weight (EFW). Methods: From 2021 to 2024, we conducted a prospective study involving 1459 singleton pregnancies. EFW was determined using standard biometric parameters—head circumference (HC), biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL), based on Hadlock’s formula. A non-parametric statistical model was applied to construct percentile charts for fetal weight. Results: In comparison with the fetal growth charts provided by the World Health Organization (WHO), INTERGROWTH-21st, and the Fetal Medicine Foundation (FMF), BFOG’s chart demonstrates that Bulgarian fetal population is statistically bigger. On the other hand, our 10th centile curve falls between those of FMF and INTERGROWTH-21st charts, which is of practical importance for timely diagnosis of fetal growth restriction in the Bulgarian population. Conclusion: The development and practical application of local fetal growth reference charts is crucial for more precise diagnoses of macrosomia and fetal smallness/growth restriction, leading to a reduction of risks for incorrect diagnoses and unnecessary medical interventions, thus providing personalized care for pregnancies.