Prevalence of Congenital Anomalies in the Northwest of Iran

Extended Abstract
Background and Objectives
Congenital anomalies, also called birth defects, are defined as structural or functional anomalies that may be identified before or at birth, or later in life. Every year, more than three hundred thousands of infant deaths occur because of congenital anomalies. Some continue to live with various types of disabilities. Low and middle income countries have higher rate of congenital anomalies. There is no long term investigation on the epidemiology and secular trend of congenital anomalies in Iran, and various prevalence rates of congenital anomalies have been reported for different parts of the country. The aim of this study was to document the time trend and epidemiological features of congenital anomalies in the northwest of Iran between 2000 and 2020, using the Tabriz Registry of Congenital Anomalies (TRoCA) programme.
Material and Methods
This study was carried out on the births registered by TRoCA in the region between 2000 and 2020 to estimate the occurrence of selected groups of congenital anomalies based on the standard coding system of the International Classification of Diseases (ICD). All infants born in three main hospitals involved in the programme are routinely examined for general health status, maturity and congenital anomalies by a clinical practitioner (gynaecologist, obstetrician, neonatologist or paediatrician) and then followed up until hospital discharge. “Passive” method for data collection was used. The registrar for data documentation were midwives. A medical coder coded the defects. Congenital anomalies for the purposes of this programme were defined based on the standard coding of ICD under one of the following main headings according to the primary diagnosis of anomaly: nervous system anomalies; genito-urinary tract, and kidney; anomalies of limb; chromosomal anomalies; cleft lip with/without palate; congenital heart disease; musculoskeletal and connective tissue anomalies; digestive system anomalies; eye and ear anomalies and other defects. Total prevalence was calculated by dividing the numerator (registered cases of congenital anomalies in the TRoCA region) by the relevant denominator (total live and stillbirths in the TRoCA region) for the same period of time. TRoCA activities have been approved by the Ethics Committee of the Tabriz University of Medical Sciences. Confidentiality and privacy are strictly considered in every part of the data gathering, processing, registration, access and reports.

Results

A total of 297,734 births were registered in the region by TRoCA registry during the study period to estimate the occurrence of selected groups of congenital anomalies based on the standard coding system of the International Classification of Diseases (ICD). Most of the infants born with birth defects were male (61.3%). The majority of infants were born live (89.6%). Although familial marriage was not reported in 60.4% of the families with an affected child, first cousin marriage was observed in 12.5% of the cases. Main type of delivery in infants born with congenital anomalies was caesarean section delivery which included 49.4% of births. An overall prevalence rate of congenital anomalies was estimated as 262.9 (CI 95%: 257.2–268.7). Anomalies of genito-urinary tract (59.2 per 10,000 births, 95% CI: 56.5–62.0), limb defects (46.3 per 10,000 births, 95% CI: 43.9–48.8), nervous system anomalies (39.4 per 10,000 births, 95% CI: 37.2–41.7), gastrointestinal anomalies (27.8 per 10,000 births, 95% CI: 25.9–29.7) and congenital heart diseases (37.1 per 10,000 births, 95% CI: 34.9–39.3) were accounted for 80% of birth defects. The lowest prevalence rates were reported for musculoskeletal and connective tissue, cleft lip with/without palate, chromosomal, eye and ear anomalies all of which collectively accounted for less than 20 per 10,000 births. Total prevalence of anomalies was more than tripled in the region over the past two decades.
Conclusion
With the control of infectious diseases and malnutrition, congenital anomalies are now making a proportionally greater contribution to ill health in childhood in many countries. According to the findings of this study, the prevalence and occurrence pattern of birth defects in a long period of time may be useful in identifying clues to the etiology of birth defects. The results may prove useful in genetic consultation, and in planning and evaluating the strategies for primary prevention of congenital anomalies, particularly in high-risk populations.
Practical Implications of Research
As a small registry of congenital anomalies in a developing country, our experiences might be of interest and useful to medical practitioners, policymakers of birth defects control programs, and those willing to set up a monitoring system of congenital anomalies in similar areas.
Ethical Considerations
This study was approved by the Ethics Committee of Tabriz University of Medical Science (IR.TBZMED.REC.1399.525). Confidentiality and privacy were observed at every stage of the program, including data gathering, data access, data analysis and reporting.
Conflict of Interest
Authors declare no conflict of interest.
Acknowledgment
The authors wish to thank the Iranian Ministry of Health and Medical Education, Tabriz University of Medical Science, and all those financially supporting the study, participating at the program, including parents and children (thesis No. 65711).