Obstetric Ultrasound is the use of ultrasound scans in pregnancy

Obstetric ultrasound can be used to:
1. Date the pregnancy and estimate the expected date of confinement (EDC)
  - this is valuable when the last menstrual period is not sure or inaccurate
  - this can be achieved by measuring the size of the fetus
2. Viability
  - when a pregnant woman has abdominal pain or vaginal bleeding, fetal viability is a concern
  - fetal heart beat can be seen
3. Determine location of fetus
  - to see the pregnancy is located in the right place (inside uterus) or abnormal place (outside uterus or called ectopic pregnancy)
4. Check the location of the placenta in relation to the cervix
  - a low-lying placenta can cause vaginal bleeding
5. Check for the number of fetuses
  - singleton or multiple pregnancy
  - multiple pregnancy is associated with more complications than singleton pregnancy
6. Check for fetal abnormalities
  - About 3% of pregnancy may be complicated by fetal abnormalities
  - the use of ultrasound can detect some fetal abnormalities
7. Assess fetal growth
  - to look for fetal growth problem
8. Assess fetal well-being
However, not all fetal abnormalities can be detected by prenatal ultrasound. Besides, false positive detection may result in patients being warned of birth defects when no such defect exists.