The prenatal diagnosis of a vasa previa can be a terrifying event for patients and their families. At Connecticut Children’s, we help patients and their families navigate the different treatment options and optimize outcomes.
Vasa previa occurs when a fetal blood vessel crosses over the cervix. The vessel(s) is unprotected by the umbilical cord and placenta, making them more vulnerable to rupture, especially when a patient’s water breaks or during labor as the cervix dilates. This condition occurs in approximately 1 in 2500 pregnancies.
Vasa previa is different from placenta previa in which the cervix is covered by the placenta.
Prior to prenatal diagnosis, the perinatal mortality rate of this condition has been estimated at 56%. However, in the context of prenatal diagnosis, survival rates exceed 96%.
Vasa previa is diagnosed with ultrasound, typically requiring both transabdominal and transvaginal scanning.
Risk factors for vasa previa include:
- History of a second trimester placenta previa or low lying placenta
- Velamentous cord insertion
- Bilobed placenta
- Multifetal pregnancy
- IVF
- Umbilical cord insertion in the lower third of the uterus at first-trimester ultrasound
Three different types of vasa previa have been described:
- Type 1 – involves a velamentous cord insertion (when the umbilical cord inserts onto the fetal membranes rather than into the placenta).
- Type 2 – involves a bilobed placenta (2 separate portions of placenta connected by fetal blood vessels)
- Type 3 – involves a normal cord insertion with a fetal vessel that runs off of the placenta, crosses over the cervix and then returns to the placenta.
The main concern in pregnancies complicated by vasa previa is rupture of the vessel which can result in fetal death. The risk for rupture is greatest in the context of rupture of the membranes and labor.
Management of patients with a vasa previa generally involves admission to the hospital around 32-34 weeks and delivery via cesarean section between 34-37 weeks.
While contemporary management of vasa previa is associated with very high survival rates (> 96%), this commonly involves prolonged admission to a hospital with a NICU. This is necessary to permit close monitoring of the patient, a rapid delivery if needed, and appropriate staff and equipment to care for a preterm newborn.
For some patients, the appropriate hospital is nearby but others have to travel a significant distance. This practice can be disruptive to families, impacting the ability of the patient to work or participate in her usual daily activities. The disruption to the individual/family unit can result in significant stress and also have financial implications. In addition, successful management includes the performance of a late preterm or early term cesarean section. This involves a longer recovery for the patient and can impact the delivery route of future pregnancies.
The team at Fetal Care Center at Connecticut Children's understands the impact that successful management of vasa previa can have on patients and their families. In response to this, we offer a fetoscopic laser procedure in appropriate candidates as an alternative option for treatment. Potential candidates for laser surgery include those with either a type 2 or 3 vasa previa and a fetal vessel within 5 cm of the cervix. Performance of this procedure obviates the need for prolonged hospitalization and enables patients to attempt a vaginal delivery at term.