There is never an ideal time to be admitted to the hospital, but new research suggests that certain days — in particular Saturdays and Sundays — may actually result in more deaths per hospital admissions than the rest of the week. It's called the "weekend effect," and hospitals around the world are struggling with ways to minimize its impact on their patients.

The harmful effect of hospital admission outcomes on the weekend has been well documented in medical papers, with research dating back to as early as 1976. Recent research has supported the theory of the weekend effect and found that the problem is true in hospitals in many developed countries around the world.

A 2015 study reviewed data from nearly 3 million admissions between 2009 and 2012 from hospitals in the United Kingdom, United States, Australia and the Netherlands. In three out of the four countries surveyed, the risk of dying within 30 days was higher for emergency admissions during weekends. It was 20 percent higher in the Netherlands, 8 percent higher in the U.K. and 13 percent higher in the U.S. Interestingly, the Australian hospitals did not seem to have a weekend effect when looking at mortality rates within 30 days of admission, but that effect was there when researchers looked at mortalities that occurred within seven days of admission.

An even more recent study found that the weekend effect may also impact the availability of donor kidneys in the U.S. Researchers found that available kidneys were less likely to be harvested from potential donors over the weekend and more likely to be discarded when they were procured on a Saturday or Sunday.

So if the weekend effect is so clearly documented, what causes it and what are hospital administrators doing to address it?

The problem is that there are likely multiple causes and therefore no one easy solution.

For starters, it's important to point out that patients who are admitted to the hospital over the weekend are more likely to come in as the result of an emergency than those admitted during the week when planned procedures and surgeries take place. Thus, it's likely that they are sicker or in more dire need of care than those admitted during the week. This is the reason that many hospital administrators give to explain the numbers, but there are probably other factors at work as well.

Weekend hospital staff are typically less experienced and specialists are less readily available over the weekends.This is evident by the fact that the patients who require immediate medical intervention, due to diagnoses such as cardiac arrests, strokes, aneurysms or head trauma, all have a greater risk of dying over the weekend than during the week.

And it's only fair to point out that hospitals are not the only places working with less experienced staff over the weekend. Lab work and other tests sent out of the hospital for processing are also more likely to experience a longer turnaround time.

The bottom line is that the weekend effect does seem to exist, and hospitals need to take a closer look at all of its potential causes so that the care their patients receive on the weekend is the same as what they would get during the week.