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Limb reduction defects in South America
E E Castilla1, D P Cavalcanti, M G Dutra
1Departamento de Genetica, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil.
British Journal of Obstetrics and Gynaecology
|May 1, 1995
Summary
This study establishes baseline frequencies for limb reduction defects in a population unexposed to prenatal diagnosis. Findings reveal prevalence rates and suggest standardizing data by maternal age due to observed effects.
Area of Science:
- Medical Genetics
- Teratology
- Public Health
Background:
- Limb reduction defects (LRDs) are potential indicators of environmental teratogenesis.
- Invasive prenatal procedures have been suggested to increase the risk of LRDs.
Purpose of the Study:
- To establish baseline frequency rates for LRDs.
- To analyze LRD data from a population not exposed to prenatal diagnostic procedures.
Main Methods:
- Utilized data from the Latin American Collaborative Study of Congenital Malformations (1967-1992).
- Clinically examined 2,917,074 newborns, identifying 1715 cases of LRDs.
- Classified and analyzed cases into 25 categories, testing for geographic and secular trends.
Main Results:
- Overall birth prevalence of LRDs was 4.91 per 10,000 liveborn infants.
- Prevalence rates differed for liveborns and stillbirths, and for isolated versus associated cases.
- Geographic heterogeneity was observed for pre-axial LRDs and amputations; maternal age affected isolated hypoplasias.
Conclusions:
- Clustering LRDs into broad groups can obscure heterogeneous entities.
- Analyzing data in a more discriminant form is preferable when associations are suspected.
- Standardizing LRD rates by maternal age is advisable due to observed effects.