Nonreassuring Fetal Status (Fetal Distress)

What is nonreassuring fetal status?

Nonreassuring fetal status (NRFS) and fetal distress are terms used to describe a baby's health late in the pregnancy or during labor. These terms are used when there is a concern that the baby may not be getting enough oxygen.

How does it occur?

The baby gets oxygen from the mother's blood as the blood passes through the placenta. If there is a problem with the blood flow to the placenta or getting oxygen across the placenta to the baby, or if there is a blockage of the blood flow from the placenta to the mother, NRFS may result. For example, NRFS may occur if:

• The placenta is not working properly.
• There is too much or too little amniotic fluid.
• The umbilical cord is pinched, flattened, or twisted. This can decrease or stop blood flow from the placenta.
• Labor contractions are too strong, too long, or too frequent. Sometimes this may result from the use of medicines to help labor, such as oxytocin.
• The mother has been given local or regional anesthesia. The anesthetic may lower the mother's blood pressure. This may reduce the supply of blood and oxygen to the placenta and, therefore, to the baby.
• The mother is lying on her back, putting pressure on the major blood vessels, which can change blood flow to the uterus.
• The mother has medical problems, such as heart, lung, or kidney problems.
• The mother develops pregnancy complications such as preeclampsia (toxemia) with increased blood pressure, placental abruption (early separation of the placenta, or injury.
• The baby has certain genetic problems or problems with the way he or she is developing.

What are the symptoms?

The mother may have no symptoms. The following signs may mean that the baby is not getting enough oxygen:

• The baby is moving less.
• The baby has an abnormal heart rate.
• Ultrasound shows a change in the baby's behavior.
• The baby's stool (called meconium) is found in the amniotic fluid when the membranes (bag of waters) rupture.
• A test of blood from the baby's scalp shows that the baby's blood is too acidic.

How is it diagnosed?

NRFS may be discovered from tests of the baby late in pregnancy or during labor and delivery.

The following tests of the baby's health might be done before you go into labor:

• An ultrasound test called a biophysical profile checks the baby's breathing movements, body movements, heart rate, and muscle tone. It also is a way to see how much amniotic fluid there is.
• A nonstress test simply monitors the baby for a short time to see if the heart rate changes with the baby's activity. Certain patterns are seen with a healthy baby or one that is becoming sick from low oxygen levels.
• Another test that is rarely performed, called a contraction stress test, checks the baby's heart rate during contractions of the uterus.

During labor and delivery:

• The baby's heart rate is watched with an electronic external or internal monitor.
• A sample of blood from the baby's scalp may be tested during labor to determine the acidity of the blood. This test is called fetal blood sampling. If the baby is not getting enough oxygen, there is more acid in the baby's blood.

If the baby has a normal heart rate during these tests, it indicates that the baby is getting enough oxygen. If the baby has an abnormal heart rate, the baby might not be getting enough oxygen. However, heart rates that are too slow, too fast, or irregular may have other causes, and they do not always mean there is a problem. For example, sometimes when the baby's head is squeezed during a contraction or delivery, the baby will have a reflex that causes the heart rate to change. Most babies can tolerate this change in heart rate very well. The delivery team will monitor the heart rate continuously during labor to see if a change is really a sign of problems.

How is it treated?

The goal of treatment is to get more oxygen to the baby. If your baby shows signs of NRFS, your healthcare provider will try to find the cause and correct it right away.

The following may be done to try to increase your oxygen level and improve blood flow to the uterus:

• Your provider may ask you to lie on your left side. The large blood vessels near the spine are less likely to be flattened by the uterus in this position.
• You may be given intravenous (IV) fluids or blood if your blood pressure drops during labor or if you are bleeding a lot.
• You may be given extra oxygen so more oxygen can get to the baby.
• If oxytocin (Pitocin) is being used to start or help your labor, the drug will be stopped or the dose lowered if the baby's heart rate is abnormal. The contractions may be too close together or too long. This can lower the amount of oxygen that reaches the baby.
• If the contractions are too strong or very close together, you may be given medicine to relax the uterus and stop the contractions.
• If the baby's heart rate shows that the umbilical cord may be pinched with contractions, your provider may ask you to change your position. Raising the foot of the bed or getting on your hands and knees may help get the baby off the umbilical cord.
• If there is not enough fluid in the baby's sac, a salt solution may be put into the sac to cushion the cord. This is called an amnioinfusion.
• If your blood pressure drops because of the epidural, you will get an IV and possibly medications.

If these treatments don't correct the problem, a cesarean delivery (C-section) may be done right away to deliver the baby. Immediate vaginal delivery with forceps or a vacuum extractor may be possible if the baby is far enough down in the birth canal and the cervix is completely dilated. A C-section will be necessary if your cervix isn't completely dilated.

The newborn will be examined right away and watched closely for problems. The baby may be put in the intensive care nursery if the distress was severe.

How long will the effects last?

For most babies, NRFS has no long-term effects after birth. However, a severe loss of oxygen for a prolonged period of time can harm babies. The damage may be mild, resulting in learning disabilities. Severe damage may result in cerebral palsy, mental retardation, or even death, but this is rare.

What can be done to help prevent NRFS?

Some problems may be prevented by careful observation and management of the mother and baby during labor and delivery. This may include a fetal monitor to keep track of contractions and how the baby is doing during labor. However, not all problems can be prevented.

Developed by Phyllis G. Cooper, RN, MN, and RelayHealth.
Published by RelayHealth.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.