Congenital limb defects occur when a portion or the entire limb fails to form normally when the baby is developing in the uterus. Many causes of congenital hand, arm and shoulder defects is unknown. However, risk factors that may increase the likelihood of a congenital limb defect include:
- Conditions affecting the baby in the uterus during development
- Exposures by the mother to chemicals or viruses while pregnant
- Specific medications