This video is unavailable because we were unable to load a message from our sponsors. If you are using ad-blocking software, please disable it and reload the page. Embed Code Restart Playing WATCH MORE VIDEOS FROM THIS EPISODE > Pediatrician Dr. Jim Sears explains that spina bifida is the most common permanently disabling birth defect in the United States. Learn what causes this potentially deadly condition, and what pregnant women can do to reduce the risk. ShareTweet