Our family doctor told me to do my best to keep my wife away from stress and unnecessary anger while she was pregnant. Later, over lunch, we had a discussion about it and he gave me some of his experiences on the subject.
Good advice.
My wife was pregnant with her daughter while her first marriage was falling apart.
The child (teen now) has been an emotional volcano her entire life, a deeply narcissistic personality.
My wife put had already put on a good deal of weight prior to becoming pregnant and put on more during the pregnancy.
The child was chunky as a youngster and is now obese.
I have no doubts about a mother’s mental condition during pregnancy affecting a child’s mental health. Certainly this is anecdotal but I see the evidence all around me that it is true.
Some would say that the divorce caused these personality traits but I was there and saw these traits in the child long before she was old enough to understand that her parents were separated.