Having a hysterectomy may cause short-term memory loss in a third of patients over 60 - study

Having a hysterectomy may increase women’s risk of developing dementia, according to new research.

Undergoing a hysterectomy to remove the uterus triggers menopause. After the surgery, many say they notice a change in their cognition, or ‘brain-fog.’

Scientists have struggled to establish a clear connection between hysterectomies, menopause and mental function.

But the new study, from Arizona State University (ASU), is the first to establish a direct link between the womb and the brain.

In experiments with rats, the researchers there found that the removal of the uterus alone - but not the ovaries - may well cause short-term memory and cognition problems.

We are in the age of mind-body medicine, where mental health is finally accepted as part and parcel of overall physical health, and the make-up of our guts is acknowledged as influencing our mood.

This revelation complicated notions old and new - especially when it comes to women’s health.

Some mental health issues like depression that were once dismissed as ‘hormonal swings’ when they affected women are now understood to be more complicated.

At the same time, so long as the mechanisms behind changes women notice - such as cognitive problems after menopause - have remained unknown, doctors have hesitated to treat them.

Similarly, research has come down on both sides of the debate over whether hormone replacement therapy (HRT) raises risks of dementia or not.

Given these related, but sometimes conflicting, bits of knowledge and uncertainty, ‘we wanted to investigate and understand whether the uterus itself could impact brain function,’ says senior study author Dr Heather Bimonte-Nelson, an ASU psychologist.

While the uterus is a crucial part of female anatomy during a woman’s reproductive years, the prevailing theory in the scientific community has long been that the organ serves no function after menopause. 

But the new study, published in the journal, Endocrinology, turns that notion on its head.

‘Our novel findings indicate the non-pregnant uterus is not dormant and is in fact linked to brain function,’ says Dr Bimonte-Nelson. 

‘This finding is striking.’

Nearly a third of all women in the US have a hysterectomy by age 60 - and some research suggests that most of these are not medically necessary and are done preventatively to treat conditions for which there are less invasive options.

So elective surgery may actually be hampering the minds of hundreds of thousands of women a year.

It seems that we don’t know as much as we believed about the female reproductive system’s role in whole-body health - though we’re starting to learn.  

‘There is some research showing that women who underwent hysterectomy but maintained their ovaries had an increased risk for dementia if the surgery occurred before natural menopause,’ Dr Bimonte-Nelson says.

But she an her team suspected that the uterus played a role too. So they tested their theory by performing a variety of menopause surgeries on rats.

The rats were divided into four groups which had either the uterus and ovaries both removed, one or other, or none at all during a dummy procedure.

Six weeks after surgery, the researchers taught them how to navigate a water maze that looked like a sunburst, with eight arms radiating out from a circular center.

The maze involved four platforms that the researchers removed when the rats found them.

The fewer platforms that remained, the greater the demand was on the rat’s memory because they had to recall both where the missing platforms had been, and where there had never been a platform.

With two platforms down and two to go, the research team found the rats that had only the uterus removed could not handle the increased memory load.

These rats kept returning to places where there had never been a platform, indicating they were unable to remember which arms of the maze led to platforms.

The other kinds of surgery did not affect how many mistakes the rats made in the maze.