I think it was stress that was hindering your mom from giving birth. Knowing that she could no longer conceive might have made her bitter. So what’s causing this infertility from anxiety? Doctors currently have no idea. Possible reasons include: It’s possible that someone in a considerable amount of stress would struggle if they were also in the process of having a child. It’s possible that as human beings evolved, those that weren’t conceiving under extreme pressure were able to live longer and conceive later than those that could. Or perhaps it was valuable as a disincentive to cause partners stress since child rearing is easier when partners are in less trouble. After billions of years, anything is possible. On a related note, perhaps extreme anxiety reduces developmental health. If stress and anxiety have any effect on pregnancy health, then maybe the human body tries to avoid it until it’s “ready.” As amazing as the human body is, it has a limited amount of resources it can handle at any given time. We know that the brain takes resources away from certain parts of the body during anxiety (this is what causes indigestion – the body takes resources from digestion to help with anxiety). It’s possible that resources needed for conception are taken away as well. But all of these are simply guesses. The truth is that the reason anxiety causes infertility is simply unclear. Stress and anxiety wreak havoc on the body, and most likely it is a combination of many different issues that make it harder to conceive.