Fetal Bowel Obstruction

The gastrointestinal tract is divided into two segments — the small intestine and the large intestine, also called the colon. In turn, the small intestine is made up of three parts: the duodenum (the segment connected to the stomach), the jejunum (where most of the liquid in food is absorbed) and the ileum (which empties into the large intestine).

There are many causes of bowel obstruction in the fetus. Most are caused by an atresia, a narrowing at some point in the small intestine. A bowel obstruction is named according to where it occurs: duodenal atresia, jejunal atresia, ileal atresia or colon atresia.

A fetal bowel obstruction is generally discovered in one of two ways.

A routine ultrasound may show a segment of bowel that is dilated, or larger than normal. This signifies a problem with the intestine. While in the uterus, the fetus constantly swallows amniotic fluid. A narrowing can slow or stop the flow of amniotic fluid in the intestine, causing it to swell and appear overly large in an ultrasound.

A bowel obstruction can also be discovered when polyhydramnios — the build-up of too much amniotic fluid — develops. Because of the intestinal blockage, the normal flow of amniotic fluid is stopped. It accumulates on the outside of the baby, inside your uterus. Your uterus may suddenly grow very large in size, alerting your doctor to a possible problem. Your doctor may then order an ultrasound, which can confirm a problem in the intestine.

If your baby has a bowel obstruction, it is important to have it evaluated thoroughly. This might entail an ultrasound, a fetal echocardiogram (a special ultrasound to look at the baby's heart) and amniocentesis. Some fetuses with bowel obstruction have abnormal chromosomes, and amniocentesis can test for this.

Your amniotic fluid level and your baby's growth should be carefully monitored. You may be at risk for early delivery, as polyhydramnios can lead to preterm labor. You and your obstetrician will determine your delivery plan.

Your baby should be born at a hospital with an intensive care nursery and a pediatric surgeon. Soon after birth, your child will have surgery to repair the abnormal piece of intestine.

The pediatric surgeon will repair your baby's intestine in one of two ways. If the narrowing is small, the surgeon may be able to remove the damaged segment, taper the dilated portion, and sew the two ends of the intestine together.

If the narrowing is long, or if the surgeon believes the intestine is damaged and cannot be used for a period of time, a temporary stoma may be placed. A stoma is a surgically created opening in the abdomen for the discharge of waste. With the stoma in place, stool will pass through the stoma rather than through the anus. The stoma is usually temporary, and the baby will need another operation to reconnect the intestine and close the stoma.

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