Your baby’s gastrointestinal tract begins developing as early as gestation week 3. In week 4, this organ develops into three regions — the fore-, mid- and hind-gut — and extends the length of the embryo, ultimately becoming the gastrointestinal tract. 
Fetal Gastrointestinal Tract Conditions
Echogenic bowel masses
Echogenic bowel masses are also known as intra-abdominal calcifications. With this condition, the intestines will appear brighter than normal on a sonogram. Around 1% of fetuses may have this condition.
Echogenic bowel masses are the most common type of echogenic mass, but these lesions can also be found in other abdominal organs. They often pose little to no risk for your baby, and about half the time, they resolve on their own without assistance.
Some causes of echogenic bowel masses include chromosomal abnormalities, cystic fibrosis, fetal infection and intra-amniotic bleeding.  They can also be caused by abnormal bowel movement or obstruction, or fetal growth restriction. .
If an echogenic bowel mass appears on a sonogram in the second trimester, the Fetal Care Center Dallas team can conduct further diagnostics to make sure it’s a true echogenic mass. If the mass is found in the third trimester, it’s typically meconium in the colon.
More information about the possible genetic causes for your baby’s echogenic bowel masses can be gathered from genetic testing, amniocentesis, a review of maternal health history and maternal blood work.
Your baby’s doctor will monitor the echogenic bowel mass over time and will perform additional ultrasound examinations in the third trimester. They may conduct further tests to look for signs of infection that could have caused the mass. Further scanning in the third trimester may be necessary to rule out a bowel obstruction.
Your doctor will also monitor your baby’s growth throughout your pregnancy to make sure an echogenic bowel mass does not contribute to intrauterine growth restriction.
Ovarian cysts (fetal)
Ovarian cysts are the most common type of abdominal cysts in a female fetus, but they can sometimes be mistaken for other types of cysts. When a fluid-filled sac on a baby’s ovaries is more than 2 centimeters in size, it is classified as a fetal ovarian cyst. 
Your doctor at Fetal Care Center Dallas needs to get a complete picture of the cyst via ultrasound to correctly diagnose and treat the condition. Fetal ovarian cysts tend to develop in the third trimester. About one in 2,500 female babies have ovarian cysts.
Fortunately, malignant ovarian neoplasms are rare in fetuses, and most ovarian cysts in fetuses resolve on their own. If postnatal surgery is needed due to torsion — twisting — or hemorrhaging, your doctor will aim to preserve the baby’s ovaries. 
Fetal ovarian cysts are not genetic. They are thought to be caused by exposure to elevated hormone levels. . A complex ovarian cyst may have been caused by torsion and may require surgery.
Ultrasounds throughout pregnancy are the best way to assess, diagnose and resolve potential ovarian cysts in your baby. MR imaging can also be helpful in some cases.
Complications of an ovarian cyst include torsion and bleeding into the cyst. An ovarian cyst can also block organs such as the bowel, which can affect the baby’s ability to swallow in utero, causing extra amniotic fluid around the baby.
In that case, or if the cyst has a diameter greater than 5 centimeters and doesn’t change in size, surgery will likely be required after birth. If the cyst is less than 5 centimeters in diameter, your doctor will continue to observe it through periodic ultrasounds. It may regress on its own without surgical intervention.
Located in the small intestine, right after the stomach, the duodenum is connected to the liver, gallbladder and pancreas. If the bowel does not develop normally while your baby is in utero, it can cause a blockage of the duodenum — an atresia or bowel obstruction. When this blockage occurs in any part of the duodenum, it’s known as a duodenal atresia. This can cause newborns to vomit starting a few hours after birth. One out of three babies born with duodenal atresia also has Down Syndrome. 
This is a rare congenital digestive disorder that typically occurs sporadically.  Blood vessel defects in the embryo may cause an absence or closure in the duodenum, resulting in an obstruction. Occasionally, duodenal atresia is due to an autosomal recessive genetic trait. .
This condition can be difficult to diagnose during pregnancy. Your doctor at Fetal Care Center Dallas will look for a dilated stomach on an ultrasound. If your baby has excess fluid in the amniotic sac, it could be a sign of duodenal atresia. Diagnosis while in utero or soon after birth can be helpful, allowing your baby’s care team to plan for early surgery after birth.
If your baby has a duodenal atresia contributing to excess amniotic fluid levels, you may be at risk for preterm delivery, and your doctor may want to induce an earlier delivery. After birth, a baby with duodenal atresia may need surgery to remove the bowel obstruction and encourage normal digestive tract functions. 
The pylorus is a muscular valve between the stomach and small intestine. Pyloric stenosis means this muscle has thickened and become enlarged, blocking food from entering the infant’s small intestine. A baby with this rare condition can suffer from forceful vomiting, dehydration, lack of weight gain, weight loss, constipation, persistent hunger or peristalsis — waves of stomach contractions after eating. Surgery may be needed to correct this condition.
The cause of this condition is unknown, but it could be due to genetic or environmental factors. Pyloric stenosis most likely develops after birth. It is more commonly seen in first-born boys of Caucasian descent. Babies born prematurely are more commonly afflicted. This disease tends to run in families. Smoking during pregnancy can double the risk of this condition. 
Pyloric Stenosis tends to develop after birth. Symptoms typically appear three to five weeks after birth. It is rarely seen in babies who are more than 3 months old.
Your baby’s doctor will check for a lump in the abdomen that is similar in shape and size to an olive. An abdominal ultrasound or radiograph can help diagnose the problem. Blood work can help diagnose and alert to possible electrolyte imbalance due to vomiting. 
Set an appointment to see your baby’s pediatrician if your baby displays any of the following: projectile vomiting after feeding, decreased energy, increased irritability, fewer wet or dirty diapers, slow weight gain or weight loss.
This is a condition that needs immediate attention to avoid possible dehydration and will most likely require surgery to relieve the blockage. Surgery to correct this condition is called a pyloromyotomy.  This can be done laparoscopically to minimize scarring, potential infections and recovery time. Most babies are able to quickly return to normal feedings after corrective surgery.
While most gastrointestinal issues during your pregnancy are not cause for concern, symptoms such as vaginal bleeding, abdominal pain or flu-like symptoms may actually be ectopic gastrointestinal symptoms, so you should reach out to your doctor immediately.
If you experience gastrointestinal distress during pregnancy, don’t be afraid to talk to your obstetrician. These issues are not always linked to problems with your baby, but your doctor can help rule out any potential problems.