Vocabulary

ep·i·de·mi·ol·o·gy  
The study of disease and health in human populations.

birth de·fect 
A problem that happens while a baby is growing inside the mother.  Not all of the baby's parts may form and work correctly.  Three out of every 1000 babies has a birth defect.  Babies with birth defects may need surgery or other medical treatments.  But they can often lead full lives if they receive the medical services and other types of help they need.  Most birth defects happen during the first 3 months of pregnancy.

em·bry·o  
An unborn baby from the beginning of pregnancy through the first 8 weeks.

spin·al cord  
A long tube of nerve tissue inside the bony spinal column, running from the brain down the length of the back.

neu·ral tube 
The tube along the back of an embryo, which later becomes the spinal cord and brain.

neu·ral tube de·fect (NTD)
Problems in the growth of the spinal cord and brain in an embryo, when the neural tube doesn't close at the top (anencephaly) or the bottom (spina bifida).  The defects occur in the first month of pregnancy, before most women know they are pregnant.  About 7 babies are born in the U.S. each day with these birth defects.