I've always brushed this kind of backstory aside, even with similar situations, but no longer! That her mother simply conceived, carried, delivered, and died without any kind of medical consultation about potential risks seems entirely ridiculous.
Include a line that she did it despite medical advice and that narrative hole is patched. Otherwise her death comes off as a entirely preventable outcome.
Of course, "weak body / constitution" is hand-wavey problematic on its own. I'm the shortest in my family (this is why I got both hand-me-down as well as hand-me-up clothes from both of my brothers, and why even my nephew who is almost 20 years younger than me is far taller than I am), I was a bit slower in school growing up, and I was born with a heart defect. While none of those descriptors are as vague as the opening one, what I actually have is Noonan Syndrome. There has to be something more that can be communicated to the reader...