Investigation of choice for diagnosis of vasa pre is:
Vasa pre : Color Doppler is the investigation of choice. A transabdominal color Doppler sonography which show 'flow' in vessels overlying the internal cervical os. A Transvaginal ultrasound with color Doppler is even better method to demonstrate this. The APT test is a biochemical test done to differentiate maternal and fetal blood when a pregnant woman presents with a vaginal bleeding episode. Most vaginal bleeding in antepaum hemorrhage are due to abruption and Placenta pre. Placental abruption (32 percent), pre (21 percent), and cervical bleeding (6.6 percent) were the most frequent causes However, when these are not confirmed , then to suspect fetal bleeding due to Vasa Pre, an APT test is done. Here, the vaginal blood is mixed with NaOH, and if the hemoglobin gets denatured ( Colorless) then its maternal blood. A positive APT test would indicate that blood is of fetal origin. A negative test indicates that the blood is of maternal origin.
APT test
Color doppler
MRI
HSG
Antepaum Haemorrhage