Does extended follow-up period after birth improve precision of diagnosis of congenital anomalies? An observational study based on the Berlin Embryotox project.

Abstract

The aetiology of congenital anomalies is often difficult to assess. Genetic abnormalities can play a role or exogenous factors such as maternal medication during pregnancy. Observational studies require reliable data on both gestational time and dosage of drug exposure during pregnancy and, if applicable, on precise description of congenital anomalies in the infant. The Berlin Embryotox Centre carried out a questionnaire-based project to investigate whether longer follow-up periods after birth lead to more accurate diagnoses of congenital anomalies. The Berlin Embryotox Centre offers risk assessment on medication during pregnancy to health care providers and pregnant women. Follow-up questionnaires asking for course and outcome of pregnancy are routinely sent out 8 weeks after the estimated date of birth. In this project, three additional questionnaires were sent to women with a singleton live-born infant, asking for paediatric findings documented along routine examinations offered to all children in Germany at the age of approximately 6 months (U5), 1 year (U6) and 2 years (U7). In addition, parents were asked to report their observations on the child's development. Data were collected between March 2019 and May 2024. A total of 3719 parents completed at least one of the three additional follow-up questionnaires. Results of the standard questionnaire 8 weeks after birth showed 138 infants with a major defect and 13 with a genetic disorder. At the end of the extended follow-up period, 180 children were reported to have a major birth defect and 39 a genetic disorder. The rate of major birth defects increased from 3.7% to 4.8%. Gain of information was largest between the examinations at 8 weeks and 6 months.

Conclusion: Extending the observation period beyond the neonatal period substantially improves diagnostic accuracy in terms of completeness and specification of congenital anomalies including genetic disorders. Studies on the risk and safety of drugs in pregnancy would benefit considerably from routine follow-up for at least 6 months after birth.

What is known: • Diagnosis of congenital anomalies is often incomplete during the neonatal period. • A longer follow-up period increases the completeness of recorded congenital anomalies.

What is new: • Regarding major birth defects, gain of information after the neonatal period is largest up to the age of 6 months. • Only one-third of genetic diseases were diagnosed during the neonatal period, a further third up to the age of 6 months.