World Health Organization fetal growth charts applied in a French birth cohort
Résumé
Objective: To evaluate the applicability of World Health Organization (WHO) fetal growth charts for abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) at the second and third trimester ultrasounds in a French birth cohort. Materials and methods: Using the ELFE cohort of live births after 33 weeks' gestation in France in 2011, we selected 7747 singletons with fetal biometric measurements at the second (20-25 weeks) and third (30-35 weeks) trimester routine ultrasounds. We calculated proportions of fetuses <3 rd and <10 th percentiles and >90 th and >97 th percentiles for AC, FL and EFW using WHO charts and two international (Intergrowth and Hadlock) and two national (Salomon and CFEF) charts. Analyses were also carried out in a subsample of 4427 low-risk births. Results: WHO charts classified 2-3% and 8-10% of fetuses <3 rd and <10 th percentiles, respectively, for AC and FL in the second and third trimesters and EFW in the third trimester. Similarly, about 3% and 10% of fetuses had AC, FL and EFW >97 th and >90 th percentile in both trimesters. Hadlock and CFEF charts also provided a good fit for third-trimester EFW <10 th percentile. For most measures, Intergrowth yielded low proportions <3 rd and <10 th percentile, and high proportions >90 th and >97 th percentiles. Proportions were slightly lower for low-risk pregnancies. Conclusion: WHO charts provided a good description of the distribution of French fetal biometric measures. Further research is needed to assess the impact of using WHO charts on obstetrical management and perinatal outcomes.