Postnatal diagnosis of congenital anomalies despite active systematic prenatal screening policies: a population-based registry study

BACKGROUND: Prenatal screening for congenital anomalies is an important component of maternity care, with continual advances in screening technology. However, few recent studies have investigated the overall effectiveness of a systematic policy of prenatal screening for con -genital anomalies, such as in France where an ultrasound per trimester is recommended for all pregnant individuals.OBJECTIVE: This study aimed to assess the proportion and the type of congenital anomalies that are not detected during pregnancy.STUDY DESIGN: The study population included all singleton fetuses and newborns with congenital anomalies from the Paris Registry of Congenital Malformations (remaPAR) from 2001 to 2021. The registry includes all live births and stillbirths at >= 22 weeks of gestation and terminations of pregnancy for fetal anomaly at any gestational age with congenital anomalies diagnosed from the prenatal period until discharge home from hospital after birth. The prevalence of postnatally detected congenital anomalies was estimated overall and for 5-year intervals within the study period. We also reported the proportion of postnatal detection by subgroups of congenital anomalies according to the EUROCAT classification.RESULTS: Of the 16,602 malformed singleton fetuses and newborns, 32.7% were detected postnatally. Of those with severe anomalies, 11.9% were detected postnatally. The postnatal detection rate decreased from 34.3% from 2001 to 2005, to 27.8% from 2016 to 2021 (P<.001). Anomalies most frequently detected postnatally were genital anomalies (n=969; 87.0%), followed by ear, neck, and face anomalies (n=71; 78.0%), eye anomalies (n=154; 74.0%), and limb anomalies (n=1802; 68.4%). Anomalies of the kidneys and the urinary tract (n=219; 7.1%) and the abdominal wall (n=37; 8.7%) were least likely to be detected after birth. Among the anomalies classified as severe, postnatal detection rates were highest for limb reduction defects (n=142; 40.6%), complete transposition of the great arteries (n=31; 17.6%), and diaphragmatic hernia (n=26; 17.2%).CONCLUSION: Despite improvement of prenatal screening over a 20-year period, our results show that there is still a margin for improvement in prenatal diagnosis of congenital anomalies.