Alamak, memang frustrating bila semua scanning ok tapi tetiba jadi premature, kan, a few of my mum friends went through the same worry, especially yang second pregnancy pulak. Macam your first case with the sudden membrane rupture at 35 weeks, kadang-kadang it's one of those things doctors can't predict even if everything looks perfect, bukan salah ibu or baby pun. Since you're already at 30 weeks with your second and doc is getting you ready for early delivery, it's worth asking your OB specifically tentang whether there might be any pattern or risk factor mereka noticed (like a cervical weakness or something subtle), because sometimes knowing helps with managing pregnancy ni and planning for labour. Kalau doc still xada clear answer, boleh consider second opinion or ask to be referred to a maternal-fetal medicine specialist, they sometimes spot things regular OB might miss. Jangan stress sangat, premature babies do really well these days, especially at 30+ weeks, so you'll likely be ok!