Ultrasound is frequently performed during pregnancy to assess the health and growth of the baby in the womb. Most women who have their prenatal exams in a hospital setting will undergo at least one ultrasound, and many mothers-to-be will have more than one at different points over the course of the pregnancy. While most of the time these sonograms turn out fine, abnormal results sometimes occur. Depending on when the ultrasound was taken and the specific abnormalities seen, the causes and followup of these results may differ.
Causes
Many different conditions may cause an abnormal ultrasound result during pregnancy. In early pregnancy, an abnormal ultrasound may reveal an ectopic pregnancy, miscarriage or signs of multiple fetuses in the womb. Birth defects, problems with the placenta, umbilical cord or amniotic fluid and unusual positioning of the baby are noticeable in second and third trimester sonograms.
Accuracy
Early ultrasounds may only be able to accurately determine the presence of severe problems such as an ectopic pregnancy or a miscarriage. A scan at between 11 to 14 weeks may detect some signs of certain diseases, such as Down's syndrome. Most structural abnormalities may not be accurately diagnosed via ultrasound until after 18 to 20 weeks gestation, according to Dr. Joseph Woo of Obstetric Ultrasound. However, prenatal ultrasound doesn't always detect abnormalities and many abnormalities that do show up turn out to be harmless to the infant in the end, making an abnormal ultrasound result insufficient for most diagnoses.
Followup
If abnormalities in the baby are seen during routine ultrasound, a more intensive followup ultrasound is typically scheduled to pinpoint the nature of the problem and its severity. Sometimes, other tests, such as amniocentesis or chronic villus sampling, can help flesh out the picture of what is wrong. These tests involve taking a sample of tissue or fluid from the womb using a needle and testing the material biochemically for disease markers.
Implications/Decisions
When a pregnant woman receives an abnormal ultrasound result involving her baby, she may have to make a decision about what to do in response to the abnormal sonogram. Some women choose to continue the pregnancy and plan with their doctors for any necessary care the baby will need after birth, including making plans for placing the baby under neonatal intensive care, scheduling any surgeries the infant may need shortly after birth or discussing options for delivering via C-section or with medical intervention to help prevent or avoid potential problems. Others may decide to terminate the pregnancy if defects are severe or if the child or family's quality of life will suffer should the pregnancy continue.
Counseling
Counseling is often recommended for women who experience an abnormal ultrasound result. While the decision of whether to continue the pregnancy or not rests solely with the woman involved, a trained genetic or medical counselor can help her understand the implications of any potential defects seen in an ultrasound scan, adding information to help her make her decision.
