Yes. Preeclampsia can affect blood flow between the placenta and your baby, and changes may show up in the umbilical artery, one of the blood vessels inside the cord. The cord itself is not usually the original problem; the concern is that the placenta may not pass enough oxygen and nutrients to the baby. Not every pregnancy with preeclampsia has abnormal cord blood-flow tests.
How can preeclampsia affect blood flow to the baby?
Preeclampsia is a pregnancy complication involving high blood pressure and possible problems with organs such as the kidneys or liver. It can also affect how well the placenta works. The placenta transfers oxygen and nutrients from the pregnant person's blood to the developing baby, helping support growth throughout pregnancy.
When preeclampsia is associated with poor placental function, the baby may receive less oxygen and fewer nutrients than needed. This can affect blood flow through the placental circulation and may lead to changes in the pattern of blood moving through the umbilical artery. According to MedlinePlus, preeclampsia is one of the conditions associated with placental insufficiency, which can interfere with fetal growth and oxygen delivery.
The distinction is important: an abnormal umbilical cord blood-flow result does not automatically mean the cord is twisted, compressed, or blocked. In pregnancies complicated by preeclampsia, clinicians are particularly concerned about whether the placenta is providing adequate support to the baby.
What does abnormal umbilical cord blood flow mean?
Blood travels between the baby and the placenta through the blood vessels in the umbilical cord. The two umbilical arteries carry blood from the baby toward the placenta, while the umbilical vein carries oxygen-rich blood back toward the baby. Blood flow is normally assessed by examining how it moves through these vessels during the heartbeat cycle.
When blood encounters greater resistance as it passes through the placental circulation, the flow pattern in the umbilical artery may change. Depending on the findings, a Doppler ultrasound may show increased resistance, reduced forward flow during part of the heartbeat, or, in more concerning cases, an absence or reversal of forward flow during that phase.
These findings can suggest that the placenta is not supporting the baby's circulation as effectively as expected. However, their significance depends on the full clinical picture, including the stage of pregnancy, the baby's growth, and other test results. A single measurement should not be interpreted in isolation.
How is umbilical cord blood flow checked?
A Doppler ultrasound is the main test used to assess blood flow through the umbilical artery when placental function or fetal growth is a concern. It uses sound waves to measure the movement of blood in the vessel. The examination is usually performed through the abdomen and does not require a needle or surgical procedure.
According to the American College of Obstetricians and Gynecologists (ACOG), umbilical artery Doppler testing can help assess placental blood flow when a baby is not growing as expected. Findings suggesting impaired placental circulation may indicate that less oxygen is reaching the baby, which is why clinicians interpret the results alongside other assessments.
Depending on the pregnancy and the initial findings, additional checks may include:
- Growth ultrasound: Measures the baby's size and estimates whether growth is progressing as expected.
- Amniotic fluid assessment: Checks the amount of fluid surrounding the baby, which can provide additional information about pregnancy health.
- Nonstress test: Records the baby's heart rate over time to assess its response to movement.
- Biophysical profile: Combines ultrasound observations with a fetal heart-rate assessment, when indicated, to evaluate fetal well-being.
These tests answer different questions. A normal Doppler result does not replace monitoring of preeclampsia itself, and an abnormal result needs to be considered alongside the baby's growth, heart-rate findings, and the pregnant person's condition.
What problems can reduced placental blood flow cause?
If placental function is impaired, the baby may not receive enough oxygen and nutrients to grow as expected. One possible outcome is fetal growth restriction, a condition in which a baby is not growing as expected for the stage of pregnancy. Reduced placental function can also be associated with lower-than-expected amniotic fluid levels or signs that the baby is having difficulty coping before birth.
The degree of concern depends on the specific findings. Some pregnancies remain stable with closer monitoring, while others develop changes that require more frequent assessments or earlier delivery. The Society for Maternal-Fetal Medicine explains in its guidance on fetal growth restriction that umbilical artery Doppler assessments are used to monitor for worsening placental blood-flow problems and help guide care when fetal growth restriction is present.
An abnormal blood-flow pattern does not, by itself, establish that a baby is in immediate danger. Clinicians look at the pattern and degree of change, how far along the pregnancy has progressed, and the results of other tests to decide what action is needed.
How is preeclampsia managed when blood flow is affected?
Care focuses on the health of both the pregnant person and the baby. The maternity team may monitor blood pressure, symptoms, blood and urine test results, fetal growth, amniotic fluid, and umbilical artery Doppler findings. The frequency of these checks depends on the mother's condition, the baby's well-being, and whether the results are stable or changing.
Management can range from outpatient follow-up with additional fetal assessments to hospital observation when closer supervision is needed. Treatment for preeclampsia may include medication to control blood pressure or reduce the risk of complications. These measures help manage maternal risks, but they do not guarantee that an underlying placental blood-flow problem will return to normal.
If continuing the pregnancy becomes riskier than delivering the baby, the obstetric team may recommend birth, sometimes before the due date. The decision depends on the pregnancy's stage, the severity and progression of preeclampsia, and the baby's test results. Johns Hopkins Medicine notes that treatment decisions for preeclampsia depend on the circumstances of the pregnancy and may include delivery when needed to protect the mother and baby.
When should you contact your maternity team?
If you have preeclampsia or are being monitored for high blood pressure during pregnancy, contact your maternity team promptly if you notice a change in your baby's usual movement pattern or develop new or worsening symptoms. Seek urgent medical assessment for a severe or persistent headache, changes in vision, significant pain in the upper abdomen, or difficulty breathing.
According to MedlinePlus, these symptoms can occur with high blood pressure complications during pregnancy and warrant medical attention. Do not wait for a scheduled ultrasound or Doppler appointment when urgent symptoms develop. A healthcare professional can assess your condition and determine whether you or your baby need immediate evaluation.
It is also important to attend all recommended follow-up appointments, even when you feel well. Placental blood-flow changes may not cause noticeable symptoms, so ultrasound and other clinical assessments can provide information that cannot be obtained from how you feel alone.