Marginal cord insertion- anyone know any information on this?

Melinda • I'm a 29 yr old, & engaged, I had B/G twins born 7/30/15 @ 33 wks. I also have a son 8 & daughter 6 yrs old ❤️
I'm 19 weeks pregnant with Twins, a boy & a girl, at my 13 weeks 6 day ultrasound the doctor thought that Baby A had a velamentous cord insertion. Today I had another ultrasound, & they were able to see more, & they looked at the umbilical cord & said it's not a velamentous, that it's a marginal cord insertion, which I've heard isn't as serious at the velamentous cord. They still want me to have a ultrasound every 4 weeks to monitor baby A's growth due to the cord, but as of right now both babies are a half of a pound. Just wondering if anyone else has this or had this with their babies? If so was there any complications with the baby or babies, & labor?