Question: can identical twins be missed at 6 weeks?
Answer: Twins can be detected on an ultrasound in the first trimester — as early as 4-6 weeks after you miss your period, and their heartbeats can be found at 6-8 weeks (it's also pretty hard to distinguish two heartbeats, and having two doesn't always indicate twins). ... Warshak, it's unlikely that a twin can be missed.