Hyperechoic bowel represents a prenatal condition that indicates an obstruction in the intestine of the fetus. Also called ecogenic bowel, the abnormality is discovered through an obstetrical ultrasound commonly performed during the second trimester of pregnancy. In some cases, a hyperechoic bowel is a normal occurrence caused when the fetus swallows blood in the amniotic fluid; the iron in blood collects in the bowel. If the condition persists into the third trimester of pregnancy, it might indicate a genetic disorder such as Down syndrome or cystic fibrosis.
A sonogram shows the hyperechoic bowel as a white area, which commonly appears brighter than the bones of the fetus. Normal fetal intestines appear black or dark gray during sonography. An obstructed bowel can begin twisting or become perforated, leading to infection. About one in 10 babies with hyperechoic bowel into the third trimester of pregnancy are born with cystic fibrosis.
As the fetus develops in the womb, the bowel usually enlarges as the fetus swallows amniotic fluid. Any fecal material that obstructs the bowel, called hyperechoic meconium, is usually passed immediately after birth. If that fails to happen, it might indicate an obstruction, especially if the baby’s abdomen is extended and vomiting is present. An enema flush may clear the bowel in some cases. Sometimes emergency surgery is needed to correct the problem.
Amniocentesis is commonly performed when hyperechoic bowel shows up on a sonogram. During the procedure, a small amount of amniotic fluid is extracted via 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 testing for 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 defects of the bowel, such as swelling, usually occur.
Other conditions may cause an echogenic bowel to develop prenatally. A blockage might develop if the fetus does not swallow enough amniotic fluid or if the placenta is damaged. A viral infection of the uterus might also lead to hyperechoic bowel symptoms that require testing of the mother’s antibodies. Obstetricians routinely monitor the pregnancy via ultrasound when any of these signs exist. Genetic counseling is commonly offered to parents when a chromosomal defect is discovered.