If your wife is 30 week pregnant, still have a chance for BB掉頭. Walk more. Walk upstairs. I had to walk up the knoll to go to work when I was pregnant. I started to walk more since 24 week pregnant until 32 week pregnant. My baby turned during the 30th week or so. When I was 32 week pregnant, already too heavy and tiring to walk loo.
Also it helps if your wife sleeps on her sides, preferable left side. Try that.