Abstract: During pregnancy, a unique and dramatic sequence of events occurs, defining the most remarkable transformation of a single cell into a recognizable human being. Ultrasonographic examination is play a important role for prevention of fetal birth defect. For some years, there have been dramatic advances in ultrasound technology, including improved spatial and contrast resolution, three-dimensional and four-dimenstional imaging, harmonic imaging, new and improved ultrasound sanning probes, and improved digital review workstations, to name a few. Likewise, our knowledge of normal fetal anatomy and pathology, and the pathophysiology of disease have increased substantially. The internet has made communication among researcheres earier. There have been many collaborative studies and refinements of the guidelines for the performance of the obstetric ultrasound examination. But there are still some differences in the approach to the obstetric ultrasound examination from one group to the others. Some issues such as what constitutes a basic ultrasound examination, what structure should be perform and interpret the examination, how safe is ultrasound, how should it be recorded and documented, how should it be reported, and how accurate rate of diagnosis fetal congenital malformation. In conclusion is that, the appeal of the ultrasound examination is that it is a noninvasive, safe procedure that has a high degree of patient acceptance and can yield a wealth of information. It is always a delight to examine the obstetric patient and reassure her about her pregnancy, when appropriate. However, there are times when an abnormality is strongly suspected but it may be equivoal or may not fit into a specific category. Under these circumstances, the best pathway for the sonologist to is to do a follow-up examination and seek consultation. If time does not allow a follow-up examination, then the sonologist should communicate to the referring physician and the patient that a definiitve answer is not possible and that decisions will have to be made with less-than-perfect information.