Blood Vessels Rupture in Pregnancy - Why Vasa Previa is Considered Fatal?

Blood Vessels Rupture in Pregnancy - Why Vasa Previa is Considered Fatal?

Pregnancy is not only a time of excitement and anticipation but also a cause for concern if you have complications. There are some conditions which can be detected by physical examination and spotting the symptoms, but some other shows no substantial signs of their presence. This becomes a complex situation for both the doctor and the patient.

Vasa Previa is one such condition that if not detected on time can cause serious complications. Scroll down to learn more about this rare condition and make sure you are not at risk.

Vasa Previa

Vasa previa is a severe pregnancy complication in which blood vessels within the placenta or the umbilical cord gets trapped between the fetus and opening of the birth canal. In other words, the vessels involved in blood circulation of the baby grow along with the membranes in the lower part of the uterus at the cervical opening.

If this condition is not detected early, then the blood vessels can rupture during the labor process, endangering the lives of both the mother and the baby. Vasa previa has been reported to occur in about 1 in 2,500 pregnancies.
Vasa previa can develop alongside placenta previa. If it remains undetected, vasa previa may lead to stillbirth.

What causes Vasa Previa?

In a normal pregnant woman, the placenta and the blood vessels of the umbilical cord are naturally shielded in the amniotic sac. But in vasa previa, the blood vessels present in the membranes are without protection. This could be because of two reasons; one is multi-lobed placenta (placenta divided into multiple pieces) or abnormal insertion of umbilical cord into the placenta (velamentous cord insertion).

The exact reason for vasa previa is unknown but following risk factors are likely to contribute:

Why vasa previa is considered deadly?

Pregnant woman with vasa previa going into labor could face serious complications. During the labor process when the cervix began to dilate (widen), the blood vessels are vulnerable to rupture. This can cause:

  • Brain hemorrhage to the fetus
  • Rapid blood loss of the baby that may result in stillbirth
  • Blood vessels becoming compressed causing lack of blood supply and drop in heart rate

If the blood vessels get ruptured, chances of dying of the baby increases before doctors are able to do anything. If vasa previa remains undetected till the start of the labor, the chances of stillbirth are as high as 95 percent.

Also Read

Abnormal Placenta in Pregnancy - Can A Woman Expect Normal Delivery With Placenta Previa?Placenta Covering Cervical Opening in Pregnancy – Complications of Placenta Previa

Diagnosing vasa previa

As vasa previa shows no noticeable symptoms, doctors can detect the markers in the second trimester using ultrasound. The doctor can also use color Doppler ultrasound to have a clearer picture of the presence of vasa previa.

Treatment of vasa previa

Vasa previa if diagnosed early in the pregnancy and before the onset of the labor, helps the doctor in treating the patients more aptly. The woman might need hospitalization in the third trimester to ensure ready and rapid access to medical care in case of rupturing of the blood vessels.

In most of the cases, doctors will be conducting C-section delivery in the third trimester, usually after 35 weeks of pregnancy. The medical team will probably be ready to provide an immediate blood transfusion. Sometimes steroids are used to mature the lungs of the baby in the event of premature delivery.

Early deliveries carry some level of risk but it is much safer than vasa previa remains undetected and the pregnancy continues normally.

Vasa Previa Mortality Rate

If vasa previa is detected early, the chances of survival for both mother and the baby would be around 97 percent. Though vasa previa cases are rare but the fatality rates are as high as 50 percent.

Are pregnant women routinely tested for vasa previa?

Generally, they are not. This is because professionals performing ultrasound are not typically trained to detect this condition. While you may always ask the doctor or the technician performing the ultrasound to spare a few minutes to document the placental cord root and ensure that you don’t have multi-lobed placenta.


1. Derbala Y et al.(2007). Vasa previa read more
2. Diagnosis and management of vasa previa(2013). American Journal of Obstetrics & Gynecology read more
3. Bohîlțea RE et al.(2016). Velamentous insertion of umbilical cord with vasa praevia: case series and literature review 
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