Placentas Fusing

Emma • 19 mo twin boys 💙💙 7mo baby boy🤰🏼 baby #4 is a GIRL 🎀 on the way!

Does anyone know anything about placentas fusing? I'm so confused! At all my scans our fraternal twin boys have always had two different placentas. I recently had our 20 week scan and I noticed on the notes it said 'fused placenta'!! I asked my ob and she said they couldn't see any gap in between their placentas?

I'm still confused..

Could their placentas have merged? Could they now be sharing one big placenta?

Please share thoughts?