I had never heard of it before but at my ultrasound today the tech saw what appears to be a very large venous lake Running almost the whole length of my placenta which is anterior. Any other ladies know about this or gone through it? I have an appointment with maternal fetal medicine to receive another ultrasound. The doctor said usually they don't even bring this up but because of the suze she wants it checked. I'm a little bit scared now. Other than that we are expecting another beautiful baby boy!