You can lie down and drink water all you want and lose a pregnancy, or go hang-gliding and
a pogo stick and
keep a pregnancy; it all depends on
whether the myriad millions of connections that have to be made as the embryo develops, all connect right. If something does not, the embryo will grow until that thing is needed, and then it will fade because that thing is not there. Not the mommy's fault, nothing she did or didn't do.