Vasa Praevia Dr Fatima Z Ashrafi DGO (Dub), FRCS (Edin), MRCOG (Lon), FRANZCOG Gisborne Hospital, New Zealand

Vasa Praevia n Rare - 1 in 3000 n Fetal vessels run in the membrane below the presenting fetal part, unsupported by placental tissue or umbilical cord n Spontaneous or artificial rupture of membranes - rupture these vessels - fetal exsanguination. n Hypoxia if the vessels are compressed between baby & birth canal. n Fetal mortality %, if not diagnosed prenatally.

Pathology n Unknown cause. n Trophotropism - tendency of a plant to lean towards sun to get light to survive. Lower segment not nourishing - placenta grows upwards to reach more nourishing tissue. n Risk factors Low lining placenta bilobed or succenturiate placenta Velamentous insertion of cord Multple pregnancies IVF pregnancies

Velamentous insertion of cord n 1% - singleton pregnancies, 8.7% - twin pregnancies, higher in early pregnancy & spontaneous abortion. n Umbilical cord usually inserts on placental mass - 99% cases. n Velamentous - cord inserted on chorioamniotic membrane. n Variable amount of cord unprotected by Wharton’s jelly. n Vasa praevia coexisting in 6% singleton pregnancies with velamentous insertion.

Velamentous insertion of cord

Twin Placenta with a succenturiate lobe

Circumvallate Placenta.

Symptoms n Asymptomatic n sudden onset of painless bleeding in 2nd or 3rd trimester or at ARM/SRM. n Heavy or small amount of bleeding. No sign symptom of Placenta praevia or abruption. n IUGR/ Congenital malformation n Maternal risk: bleeding

Antenatal Diagnosis n An avoidable tragedy. n Changing ultrasound protocol for checking placental cord connection. n Can be diagnosed as early as 16 weeks. n All suspected cases should be checked for vasa praevia n Level 2 scan of LUS and/or transvaginal scan with color doppler.

Doppler scan to detect Vasa praevia - 1

Doppler scan to detect Vasa praevia - 2

Management n If diagnosed prenatally tocolytics, bedrest no vaginal exams avoid heavy lifting, straining during bowel movement regular scans n Planned cesarean section can circumvent fetal risks. n Delivery can be planned early enough to avoid emergency, but late enough to avoid prematurity n Baby requires aggressive resuscitation & blood transfusion

Management n If PV bleeding intrapartum Speculum - fetal vessels. Investigate for the source of bleeding Apt test - fetal hemoglobin is alkali resistant. Wright stain of blood smear. If fetal bleeding confirmed, immediate cesarean section.