Amniotic band sequence and limb defects: data from a population-based study.

Cases with amniotic bands were analysed separately as part of an ongoing study of limb defects occurring among 1,213,913 liveborn infants in British Columbia during the years 1952 to 1984. A total of 24 cases with this specific condition was identified among 659 cases with limb defects. The calculated incidence for amniotic band sequence with significant limb involvement was 0.19 in 10,000 livebirths. This is a minimal incidence, as cases without defects of the limbs, but with constriction rings were not identified with this approach. Familial cases and cases with additional anomalies were found.