Hyperechoic bowel represents a prenatal condition that indicates an obstruction in the intestine of the fetus. Also called echogenic bowel, the abnormality is discovered through an obstetric ultrasound that is commonly performed during the second trimester of pregnancy. In some cases, a hyperechoic intestine is a normal occurrence caused when the fetus swallows blood in the amniotic fluid; Iron in the blood accumulates in the intestine. If the condition persists until the third trimester of pregnancy, it could indicate a genetic disorder such as Down syndrome or cystic fibrosis.
An ultrasound shows the hyperechoic intestine as a white area, which commonly appears brighter than the bones of the fetus. Normal fetal intestines appear black or dark gray on ultrasound. A blocked intestine can begin to twist or become perforated and lead to an infection. About one in 10 babies with hyperechoic gut in the third trimester of pregnancy is born with cystic fibrosis.
As the fetus develops in the womb, the intestine generally enlarges as the fetus swallows amniotic fluid. Any fecal material that blocks the intestine, called hyperechoic meconium, is usually passed immediately after birth. If that doesn't happen, it could indicate an obstruction, especially if the baby's abdomen is extended and there is vomiting. An enema flush can clean the intestine in some cases. Sometimes emergency surgery is needed to correct the problem.
Amniocentesis is commonly done when hyperechoic bowel shows up on ultrasound. During the procedure, a small amount of amniotic fluid is removed through a thin needle inserted through the abdomen. The woman's body replaces the fluid within a few hours after the test.
Amniotic fluid contains cells that continue to divide. After about 10 days, there are enough cells to begin analyzing chromosomal defects. Down syndrome is the most common genetic disorder discovered during amniocentesis, especially if one or both parents carry the gene that causes it. If a genetic disease is present, additional bowel defects, such as bloating, usually occur.
Other conditions can cause an echogenic bowel to develop prenatally. A blockage can develop if the fetus does not swallow enough amniotic fluid or if the placenta is damaged. A viral infection of the uterus can also lead to hyperechoic bowel symptoms that require testing of the mother's antibodies. Obstetricians routinely monitor pregnancy by ultrasound when any of these signs are present. Genetic counseling is commonly offered to parents when a chromosomal defect is discovered.