Hi T_pup, my girls were Di Di. They picked up on a size difference at 28 weeks. A also had reduced fluid in her sac.
I don't think we were IUGR, were never given a medical term but she was small for dates. We were on weekly scans from 28 weeks. (Growth every 2nd week and just doppler scan weekly)
We made it to 35 weeks at which point A hadn't grown in a week and also there was increased resistance in the placenta so the decision was made to deliver.
I had a c-section as A was the second twin, and with no previous labour history, they didn't know how she would do with 2 labours.
At birth she was 1.65kgs and E was 2.25kgs. We spend 10 days in NICU. A was fine when she was born (incubator for 3 days and then just needed to grow). E needed CPAP for 3 days.
This was as the doctors had suspected as A had been under stress pre birth whereas E had just been cruising along and whipped out unsuspectingly