Being an expectant mother, you will find it reassuring to know that your baby will be born healthy with no congenital deformities. An ultrasound scan can be used for screening to look for abnormalities in the physical structure of the baby, for example in the heart, lungs, spine, brain, long bones in legs or arms, organs in the abdomen like liver, stomach, intestines, kidneys, bladder and even check for cleft lip and palate. Finding of certain abnormalities during an ultrasound scan may also alert doctors to the possibility of Down Syndrome or other genetic abnormalities in the baby. Further testing can then be done to exclude these. Ultrasound screening for physical abnormalities is usually done during around the fifth month or 20th week of your pregnancy. It is performed by a sonographer or obstetrician, using a fairly advanced ultrasound machine that provides excellent resolution for imaging. The accuracy of scans is about 70% in detecting all abnormalities.