I think it's not only the ability to know you are pregnant earlier that has changed attitudes to miscarriage. Since the legalisation of abortion and the availability of the pill, most unwanted pregnancies will not have occurred or will already have been terminated before 12 weeks.
Miscarriages today will almost always be a disappointment at the very least and a distressing bereavement for some. With the trend to have babies later, there are fewer years to try to conceive and greater difficulties in achieving it.
Although women who suffered miscarriages of a much wanted child in the past suffered just as much - especially as there was no IVF or fertility treatment, there was a greater proportion of those for whom a miscarriage was a relief. After all, before legalised abortion, women risked their lives at the hands of back-street abortionists or DIY methods involving gin, a hot bath, and jumping down the stairs. It was a disgrace to be an unmarried mother and there was no help from the state to bring up a child on your own. Even for married couples, another pregnancy was often bad news, when the family budget was already stretched to the limit. That was bound to affect the way miscarriage was perceived.
Whereas now, even when a woman has terminated a pregnancy, there seems to be pressure on her to feel sadness, and that there's something unnatural about her if she doesn't. Context is everything.
Yet, in 50 years, the incidence of miscarriage hasn't changed. One in four pregnancies are likely to fail in the first trimester. I think we should remember that times have changed and be as sympathetic as possible when this happens, but, at the same time, hold back a bit on the celebrations for a positive test and building hopes and dreams for the future so as not to increase the heartache if they come to nothing.