GAIA Level 1 Vasa Previa

**Semantic type:** Classification

**Definition:** GAIA Level 1 Vasa Previa is defined by two criteria: first, second trimester ultrasound evidence of fetal vessels (vessel with fetal heart rate identified by color flow Doppler) traversing the membranes and overlying the internal cervical os; second, post-delivery examination of the placental specimen that demonstrates unsupported fetal vessels within the membranes.

**Synonyms:** - Global Alignment of Immunization safety Assessment in pregnancy Level 1 Vasa Previa - Level 1 Vasa Previa