What Is Placental Insufficiency?

In placental insufficiency, the placenta—the organ that provides nutrients and oxygen to a developing fetus in the womb—isn’t working properly. This can mean that the developing baby doesn’t get enough of the oxygen and nutrients it needs for proper growth. 

Medical professionals often use the terms "placental insufficiency" and "placental dysfunction" interchangeably. Another term for it is "uteroplacental vascular insufficiency." It affects roughly 8% of all pregnancies.

Placental insufficiency is associated with other important problems of pregnancy, including preeclampsia and something called intrauterine growth restriction, in which the baby doesn’t grow as much as it should. Both may lead to preterm labor and other issues.

The following article discusses placental insufficiency in more detail, including the medical problems it can lead to, its underlying causes, diagnosis, treatment, and related issues. 

Medical Problems From Placental Insufficiency

Placental insufficiency can cause babies to be smaller than expected for the number of weeks of pregnancy (sometimes called "small for gestational age," or SGA). This often happens because of something called "intrauterine growth restriction" (sometimes also called "fetal growth restriction," or IUGR).

Because it isn’t getting all the oxygen and nutrients that it needs, the developing fetus doesn't grow as much as normal. Placental insufficiency isn't the only potential cause of IUGR, but it's a major one.

Fetuses with IUGR generally have a weight that is lower than 90% of other fetuses of that same age. 

Risk of Stillbirth

Fetuses who are small for their age have an increased risk of being stillborn compared to babies who are average in size. Placental insufficiency causing IUGR is one of the biggest risk factors for stillbirth.

Additional Medical Problems in the Infant

Infants born to a mother with placental insufficiency are also more likely to have certain medical problems after birth. Some of these are:

• Low blood sugar (hypoglycemia)
• Increased bilirubin in the blood (hyperbilirubinemia)
• Low levels of calcium in the blood (hypocalcemia)
• Serious infection of the intestines (necrotizing enterocolitis)

These and/or other potential issues might mean that a baby needs care in a neonatal intensive care unit after delivery. 

Preeclampsia

Preeclampsia is a medical condition that causes symptoms like very high blood pressure, headaches, and swelling in the mother. Scientists are still learning about the relationship between preeclampsia and placental insufficiency, but preeclampsia may be more common in people with placental insufficiency.

In preeclampsia, researchers also have found reduced blood flow to the placenta. It may be that placental insufficiency is one of the causes of preeclampsia in some people.

Both IUGR and preeclampsia are risk factors for preterm labor. Babies born significantly before their expected due date are more likely to have health problems, like difficulty breathing. They are more likely to need to spend an extended time in the hospital, perhaps in a neonatal intensive care unit.

What Causes Placental Insufficiency?

Placental insufficiency happens when the placenta isn’t working well. Normally, this organ, which develops during pregnancy, gives plenty of oxygen and nutrients to the developing baby. That helps the fetus grow larger in size and weight. 

But sometimes the placenta has a problem and can’t do its job well. Depending on the situation, this might be just a mild issue or something that makes a big impact on the developing baby. 

Sometimes this happens because the mother just isn't getting enough food to eat. Other times it has to do with problems with the placenta itself. Some examples that can cause this are:

• Problems with the formation of the blood vessels in the placenta
• Abnormalities of the umbilical cord
• Placenta previa (when the placenta partly covers the outlet for the uterus)
• Tumor of the placenta 

But sometimes a problem with the mother’s health might cause placental insufficiency. For example, this might happen in a woman who had long-term high blood pressure, or in someone who had high blood pressure due to their pregnancy.

Other diseases in the mother associated with placental insufficiency are:

• Anemia (lack of healthy red blood cells)
• Diabetes
• Heart disease
• Lung disease

Smoking, excess drinking, and drug use might also increase your risk. However, the exact problem causing placental insufficiency is often not known. 

Diagnosis of Placental Insufficiency

Your healthcare provider may determine that your baby is smaller than expected during a normal obstetrical exam. They might start to be concerned about this if the uterus isn’t as tall as expected when they feel and measure your belly.

This can be checked on a normal pregnancy screening test, an ultrasound, which uses sound waves to give an image of the baby. It can also give a good estimate of the baby's weight.

Low Fetal Weight

If the fetus is a lower weight than expected (compared to others at that point in the pregnancy), placental insufficiency may be an issue. However, some infants are smaller than they should be (that is, they have IUGR), because of different medical problems like an infection or a serious genetic birth defect.

However, some of these infants are perfectly healthy—they are just on the small side because they have inherited genes for this from their parents. So even though the medical team might be initially concerned about placental insufficiency causing a low weight, the baby might be growing completely normally.

However, some infants might not be gaining weight normally (perhaps due to placental insufficiency), but their weight might be just a little too high to meet the standard criteria for low estimated weight. They might have been getting enough nutrients early in the pregnancy, but not near the end of it. These fetuses may also be at higher risk of medical problems, like stillbirth. 

Artery Analysis

Doppler ultrasound, a test that uses sound waves to look at how blood flows through certain vessels, can also give some clues about IUGR and possible placental insufficiency. This test can be done at the same time as a regular pregnancy ultrasound. Doppler ultrasound can detect:

• Umbilical artery: In a fetus with IUGR, the umbilical artery, which carries waste products from the fetus to the mother, may show abnormalities in terms of its blood flow, as may the uterine artery (which carries blood to the uterus). These can also give diagnostic clues.
• Middle cerebral artery: Another clue is in the blood flow in an artery that is going to the infant’s brain (called the middle cerebral artery). Infants not getting enough nutrients often compensate by channeling more of the available blood to their brain. 

Through analyzing the relationship between these arteries, your healthcare provider may get some clues about whether placental insufficiency might be a problem. 

In some cases, your healthcare provider might recommend a non-invasive imaging test called a fetal magnetic resonance imaging (MRI). This test uses magnetic fields to get more detailed information about the baby and the placenta.

Treatment of Placental Insufficiency

Unfortunately, placental insufficiency can't be cured or treated directly. But there is a lot that can be done to manage the problem and increase the chance of a healthy pregnancy. 

Monitoring is a key part of treatment for placental insufficiency. Your medical team will keep a very close eye on you and your baby. This will be through your regular obstetrical (OB) appointments—and sometimes additional ones. This monitoring is very important for giving you the best chance at a healthy pregnancy and baby. 

Key monitoring tests might include:

• Regular pregnancy ultrasound (to estimate size and see how the baby is moving)
• Doppler ultrasound (to see how blood is flowing through key vessels)
• Fetal heart monitoring (to look for patterns that show that the baby is distressed)

Your medical team will also ask you to keep track of how much the baby is moving and let them know if it seems to be moving less.

The Pregnant Parent's Health

It’s also important that the mother is monitored to stay as healthy as possible. If you have a medical condition that might be contributing to placental insufficiency (like high blood pressure), you’ll get treatment for that. 

It’s also important that the mother eat a good diet with enough nutrients to help her gain a healthy amount of weight. Putting the pregnant person on bed rest may also help improve blood flow to the baby.

Planning for Delivery

If it seems like the baby is compensating well, your medical team will likely want you to maintain your pregnancy as long as possible. However, if the baby shows clear signs of distress, your healthcare provider might need to induce labor so you can have your baby early. 

In some cases, your doctor might recommend a planned Cesarean delivery (C-section) to reduce stress on the baby during delivery. 

If you have placental insufficiency, you may find it helpful to work with a specialist trained in high-risk pregnancies. If the problem is severe, you might need monitoring in the hospital. 

Summary

Placental insufficiency is a problem in which the placenta isn’t delivering enough nutrients and oxygen to the developing baby. It is one of the most common causes of intrauterine growth restriction (IUGR), which causes the baby to be smaller than it should be.

Placental insufficiency may increase the risk of other problems, like stillbirth, preterm birth, preeclampsia, and other infant medical issues.

Ultrasounds of the baby and of blood flow through important blood vessels can help diagnose placental insufficiency. There are not good treatments for it. However, with lots of monitoring, your medical team can help manage the issue, giving you the best chance of a healthy pregnancy.

A Word From Verywell

It’s hard not to worry if placental insufficiency may be causing problems with your baby’s growth. Know that it’s not your fault. It’s easy to jump to conclusions. In fact, many babies dealing with placental insufficiency will go on to live healthy lives. Attending your medical appointments, eating well, and avoiding drugs, alcohol, and smoking will improve your chances of a healthy pregnancy.