Risk Factors for Anorectal and Associated Malformations in German Children: a 10-year Analysis

Background: Incidences of anorectal malformations (ARM) occur in 1 of 2000 - 5000 live births and up to 64% have associated malformations (ARMa). Aim was to evaluate possible prenatal risk factors for ARM .

Methods: Case-control design was used to compare risk factors in ARM (n=44) to a control group (CG; n=26). We used modified prenatal questionnaires, analyzed mothers` prenatal records and participants completed a structured interview. Endpoints were medical history, drug consumption, occupational risk factors, and time point of diagnosis, associated malformations and sensitivity of radiological imaging.　

Results: Our results showed that ARM couples had a significantly higher age-difference (p=0.028). ARM mothers had more abnormalities during pregnancy (p=0.002), more positive vaginal smears of group B streptococci (p=0.024), urogenital infections (p= 0,005), gestosis (p=0.03), emesis (p=0.025) and higher numbers of chronic diseases (p=0,018). ARM mothers took less medications during pregnancy (p=0.013) including folic acid (p=0.041);, their intake of iodine tablets was significantly higher (p=0.035) and they continued smoking longer (p=0.036) than CG mothers, which had more stillbirths (p=0.035). Using illegal drug and alcohol, both groups did not show significant differences. ARMa was present in 68.1% (n=30), of which 45.5% were of urogenital origin (n=20). In 72.7% ARM diagnosis was made on the first day of life (n=32), while in 12 patients diagnosis was delayed (27.3%).

Conclusion: A combination of different risk factors seem to be associated with the development of ARM, which takes place at an early stage (<7.week) of pregnancy. Therefore, risk factors influencing fetal development later must be critically considered. A delayed diagnosis rate of 27.3% is too high and has to be improved. We advocate an interdisciplinary assessment in unclear clinical findings already on first day of life to better support parents, optimize therapy and positively influence the outcome.