Risk factors for anorectal and associated malformations in German children: A 10-year analysis

Incidences of anorectal malformations (ARM) occur in 1 of 2000-5000 live births and up to 64% have associated malformations (ARMa). The aim of the study was to evaluate possible prenatal risk factors for ARM in a tertiary hospital.

A 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.

Our results showed that ARM couples had a significantly higher age difference (p = 0.028) compared to CG. 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 medication during pregnancy (p = 0.013) than CG mothers including folic acid (p = 0.041); their intake of iodine tablets was significantly higher (p = 0.035) and they continued smoking for longer (p = 0.036) than CG mothers, and they had more stillbirths (p = 0.035). In using illegal drug and alcohol use, the groups did not show significant differences. ARMa was present in 68.1% (n = 30), of which 45.5% were of urogenital origin (n = 20). ARM diagnosis was made on the first day of life in 72.7% (n = 32), while diagnosis was delayed in 12 patients (27.3%).

A combination of different risk factors seem to be associated with the development of ARM, which takes place at an early stage (<7th week) of pregnancy. Therefore, risk factors influencing fetal development must be critically considered. We advocate an interdisciplinary assessment in unclear clinical findings on first day of life to optimize the therapy and positively influence the outcome.