Supplementary Material for: Optimal strategies for screening common birth defects in children of lower- and middle-income countries: a systematic review

Introduction Congenital anomalies are one of the major causes of the global burden of diseases, and low- and middle-income countries (LMIC) are disproportionately affected. This review assesses the prenatal and postnatal screening methods and compares the prevalence of major congenital anomalies in LMICs. Methodology We conducted a systematic search in MEDLINE/PubMed, CINAHL, Cochrane databases of systematic reviews, clinical trials.gov for relevant studies using Medical Subject Headings (MESH) and keywords. We categorized the studies into different systems and screening methods depending on the time the tests were conducted (prenatal or post-natal). The studies were then subjected to detailed descriptive analysis. Results A total of 59 studies were selected for analysis; these focused on screening methods for congenital anomalies and compared their prevalence with regards to different systems. The most common screening techniques both prenatal and post-natal included antenatal ultrasound, fetal echocardiography, pulse oximetry and clinical examination. The most common congenital abnormalities involved the central nervous system (neural tube defects) and musculoskeletal (clubfoot), followed by gastrointestinal (omphalocele and gastroschisis) and cardiovascular (structural heart defect) . Overall, different systems had varying prevalences of different birth defects, ranging from 0.28 to 8.5%. In contrast, the prevalence of musculoskeletal system disorders varied from 1.01% to 3.96%, in the cardiovascular system from 0.57% to 10.4%, and in the urogenital group from 0.83% to 5.9%. Conclusion: The review highlights the lack of screening programs and studies especially in the primary and secondary care settings in LMICs, and limited studies do indicate a high burden of various congenital anomalies. There is a need for guidelines and programs in global maternal and child health programs to include timely screening and management of common birth defects in LMICs.