I had a friend who fell pregnant during the PGCE (Early Years) year - she was around 8 months when we graduated. She found the final placement hard work, but overall coped. The tutors and teachers were supportive, although she didn't get on with her placement partner which didn't help.
Perhaps it depends which Uni you go to and I also think it depends what you're used to but, whilst the PGCE was hugely enjoyable and challenging, I didn't find it that hard after working fulltime in a stressful career - there were many weeks in college where I had so much free time I didn't know what to do with myself and ended up doing things like typing up my lecture notes to feel 'busy'. But... I was used to working with computers (people who weren't found it much harder), used to studying (albeit I'd finished my MA 5 years earlier), used to working hard at a 'profession' (again some people straight from Uni who weren't used to being in a professional workplace really struggled - and 2 of them ended up failing and needing to re-do placements), and determined to do well so I was very organised (use colour coded timetables, lesson plans and organise your placement folders neatly - the teachers/tutors were bizarrely impressed).
Sorry that sounds like I'm full of myself, but I just think I was in the right place to do well in the PGCE and possibly could have coped with being pregnant as well, but only you know what place you're in and how much support you have?! I'd second that the NQT year was much, much harder than the PGCE (I was in an inner London school, whereas my teaching practices were more rural ones) and more stressful and I definitely couldn't have coped with being pregnant too - but you have 4 years to complete your NQT year after graduating (or you did when I qualified).
Also, I went into teaching partly because of the family friendly aspect, but decided not to go back to my job after my maternity leave. I'm now childminding and being a teacher is a real selling point, so my PGCE wasn't wasted and I do see myself going back into teaching in the future.