Circumvallate placenta is a rare condition that occurs when the amnion and chorion fetal membranes of the placenta fold backward around the edges of the placenta.

The placenta helps a fetus grow properly by channeling nutrients and oxygen from the pregnant person. Placental abnormalities, such as circumvallate placenta, can harm the developing fetus.

Sometimes, a doctor may discover a circumvallate placenta using an ultrasound. In other cases, they may not diagnose the condition until delivery.

In this article, we discuss the symptoms and treatment of a circumvallate placenta and explain how it can affect pregnancy and birth.

a doctor doing an ultrasound to try and detect circumvallate placentaShare on Pinterest
An ultrasound may reveal a circumvallate placenta.

A circumvallate placenta does not always cause symptoms during pregnancy. However, a doctor may be able to notice some signs that a woman has a circumvallate placenta.

These signs may include:

Vaginal bleeding

A circumvallate placenta leads to a higher chance of persistent vaginal bleeding during the first trimester.

A study involving 92 women with a circumvallate placenta found that the incidence of vaginal bleeding was higher in these women than in those in the control group during all three trimesters.

However, the authors note that the results may not be fully representative of the general population, as the study included such a small number of women.

Premature rupture of membranes (PROM)

PROM occurs when the amniotic sac breaks before the onset of labor, and it can affect up to 8% of pregnancies. If the rupture happens in the first 37 weeks of pregnancy, doctors refer to it as preterm PROM (PPROM).

PROM has several possible causes and risk factors. However, if a woman experiences PROM alongside vaginal bleeding in the second trimester, she may have a circumvallate placenta. The doctor will investigate further.

Inhibited fetal growth

A fetus may grow more slowly in a woman with a circumvallate placenta.

If a baby is not meeting expected growth points during checkups, a doctor will likely order tests to try to determine what is causing this issue.

Circumvallate placenta can affect both the pregnancy and delivery.

How does it affect the fetus?

Doctors believe that a circumvallate placenta can cause several different issues.

The findings of a 2014 study revealed the following complications in the participants with a circumvallate placenta:

  • Preterm delivery: Early delivery affected 64.1% of the women.
  • Placental abruption: In this emergency, the placenta suddenly detaches, putting the fetus at risk. Placental abruption affected 10.9% of the women.
  • Increased risk of neonatal death: Neonatal death occurred in 8.9% of cases.
  • Increased risk of needing neonatal intensive care unit admission: Of the infants born in the study, 55.4% required neonatal intensive care.
  • Chronic lung disease: This condition affected the infants belonging to 33.9% of those in the study.
  • Emergency cesarean delivery: This procedure was necessary in 46.5% of cases.

However, according to some recent evidence, a circumvallate placenta may not be responsible for some of these issues.

In a 2018 study, researchers compared women with a circumvallate placenta with women who did not have the condition but had otherwise similar backgrounds.

The results showed that in 268 matched cases, no significant difference existed between the individuals regarding lower birth weight, preterm delivery placental abruption, or other issues.

The study authors also noted that routine obstetric care is effective in helping women with a circumvallate placenta.

Doctors do not know the exact cause of circumvallate placenta, and there does not seem to be anything that a woman can do to stop a circumvallate placenta from forming.

It is a rare condition, affecting about 1–2% of pregnancies.

Circumvallate placenta is difficult to diagnose during pregnancy. Doctors most often diagnose the condition when they examine the placenta after delivery.

However, a woman typically has several routine ultrasounds during pregnancy, and a doctor may notice the condition during these scans.

If a doctor does diagnose a circumvallate placenta before birth, they may recommend ways to help reduce the risk of lower birth weight and placental abruption.

Although there is no way to treat a circumvallate placenta, a doctor may take some steps to help reduce the risk of complications or treat them.

One of the primary concerns of a circumvallate placenta is the decreased birth weight of the baby. To help monitor this, a doctor may recommend more growth checks using ultrasound.

If the fetus is not growing fast enough, the doctor may recommend early delivery. A vaginal delivery will usually be possible, but a cesarean section might be the best option if the baby is not tolerating labor.

If a woman has a placental abruption as a result of a circumvallate placenta, a doctor will usually recommend frequent monitoring, hospital bed rest, early delivery, and, sometimes, an emergency cesarean section.

Although some evidence exists to indicate that a circumvallate placenta can cause a higher risk of low birth weight or other complications, other research suggests that the increase in risk may not be significant.

However, this condition can occasionally result in the loss of the baby. Proper medical care and monitoring are, therefore, essential to help minimize the risk of complications.

A doctor cannot directly treat the circumvallate placenta, but they can take steps to help reduce the risk factors for the woman and baby.

Circumvallate placenta is an abnormality of the placenta. It causes the membranes of the placenta to fold back around its edges.

It can increase the chance of complications such as preterm delivery and placental abruption, as well as increasing the risk of neonatal death and an emergency cesarean.

There is no treatment for a circumvallate placenta, and doctors often do not diagnose it until after the birth. However, if they can diagnose it before delivery, they may be able to take steps to help control the effects.