1. Verify whether or not the mother is pregnant, when pregnancy tests and the usual signs of pregnancy are unclear.
2. Detect a possible ectopic pregnancy . 3. Obtain a more precise determination of baby’s gestational age when there is a discrepancy between uterine size and estimated due date. In the first half of pregnancy ultrasound can accurately date baby’s gestation within 7 to 10 days. In later months it is not as accurate and is useless for dating the pregnancy.
4. Evaluate baby’s growth if other signs, such as uterine size, suggest a problem.
5. Determine the cause of unexplained bleeding.
6. Confirm how baby lies in the uterus (breech, transverse, vertex) if the clinical signs are unclear late in pregnancy.
7. Detect suspected multiple pregnancies if mother’s uterus is growing faster than expected.
8. Detect problems with the placenta, such as placenta previa (the placenta being positioned too low or over the cervix) and abruptio placentae (the placenta is separating prematurely, causing bleeding).
9. Measure the amount of amniotic fluid if mother is losing amniotic fluid or not replenishing it at a normal rate.
10. Detect abnormalities of the uterus, especially in women with a history of previous miscarriages or problem pregnancies.
11. Detect developmental abnormalities in the growing baby that would influence where baby should be delivered and what preparations need to be made beforehand. Abnormalities of heart, lung, and intestinal development can, if detected early, alert parents and healthcare providers to deliver the baby in facilities equipped to begin management immediately after birth. Oftentimes, early recognition and early treatment can be lifesaving.
12. Assist in medical or surgical procedures: amniocentesis, chorionic villus sampling, trying to turn a breech baby, fetoscopy, or intrauterine transfusion.