It’s not your imagination: your dreams really have gone off the rails during pregnancy! Research has shown that vivid dreams during pregnancy are caused by a combination of fluctuating hormones- (including high levels of progesterone) and heightened emotions (like all that anxiety you’re having about your mother-in-law asking if she can be in the delivery room while you’re in labor).
You also may not be sleeping that well thanks to all those physical discomforts, like an aching back, morning sickness and leg cramps. Poor sleep can cause an increase in intense dreams too.