The prevalence of amnion rupture sequence, limb body wall defects and body wall defects in Alberta 1980-2012 with a review of risk factors and familial cases.

Prevalence rates of amnion rupture sequence, limb body wall defect, and body wall defects vary widely. Comparisons are difficult due to small case numbers and the lack of agreement of definition, classification, and pathogenesis. This study reports the prevalence of cases classified in five distinct categories. The Alberta Congenital Anomalies Surveillance System data on live births, stillbirths, and terminations of pregnancy (<20 weeks gestation) occurring between 1980 through 2012 with the ICD-10 Royal College of Paediatrics and Child Health Adaptation codes used for congenital constriction bands (Q79.80) and body wall complex (Q89.7) were reviewed. During the 33-year-study period, there were 153 eligible cases ascertained from 1,411,652 live births and stillbirths, giving a prevalence of 1.08/10,000 total births. There were more males (52%) than females (45%) and 3% were of unknown sex. The average maternal age, birth weight, and gestation was 27 years, 2,701 g, and 35 weeks, respectively. Limb deficiencies occurred in 78% of cases. Amniotic bands with limb deficiency was the most common phenotype (48%). Digital limb deficiency was the most frequent type (56%); however, cases with body wall defects had more severe types of limb deficiencies. The upper limbs only were affected more times (44%), and there was no side preference. Most cases are sporadic but a number of familial occurrences have been reported although some have insufficient documentation and others misdiagnosed. A review of putative risk factors gives conflicting results.