Margaret was reassured to see the heart beat and to see her baby move. An ultrasound done at this point in pregnancy is helpful for confirming or helping to establish your due date. If two or more fetuses are present, they can usually be seen. In many cases, fetal problems can also be seen at this time. Tip for Week 20 An ultrasound test done at this point in pregnancy may make it possible to determine the sex of the baby, but the baby must cooperate.
Sex is recognized by seeing the genitals.
Even if the sex looks obvious, ultrasound operators have been known to be mistaken about a baby's sex. The advantage of the test is that results are available in a few days. The disadvantage is it carries a slightly higher risk of miscarriage than amniocentesis. Guided by ultrasound, a fine needle is inserted through the mother's abdomen into a tiny vein in the umbilical cord. A small sample of the baby's blood is removed for analysis.