If you haven't put any effort into saving for retirement, it's something worth considering -- and soon.

That's because while few Americans are superstar retirement savers, women in particular tend to fall short on retirement savings compared to men, saving less than 70% of what men typically save, according to a recent report by the ING Retirement Research Institute.

So why is saving such an uphill battle for women? Here are some of the key factors:

1. They Live Longer

Retiring comfortably means setting up a steady stream of income that will last for life. The additional burden on women here stems from the fact that they tend to live about five years longer than men.

This means their savings have to stretch farther, and perhaps cover the increasing healthcare expenses that come with old age. That may be why so many women rely heavily on Social Security; it accounts for 67% of income for women over 65, compared to 56% for men, according to the 2010 Current Population Survey Annual Social and Economic Supplement.

2. They Earn Less

Whether because of the glass ceiling on women's wages or the time many women spend raising children, women earn less than men over their working lives -- a lot less. According to the 2008 Center for American Progress Action Fund report, 'Lifetime Losses: The Career Wage Gap,' women make $434,000 less than men over their lifetime. This clearly puts women at a disadvantage when it comes to saving.

3. They Avoid Risk

There are two sides to saving for retirement: what you put in, and how you invest that money to make it grow. And one of the fundamental factors in investment returns is risk. That's why few advisors recommend a risk-free portfolio, especially for younger investors.

For women, however, biting the bullet often isn't a strong suit. Only 26% of them feel confident in their investing ability -- compared to 44% of men -- according to a 2011 survey by MassMutual Financial Group. As a result, women trade less frequently, hold less volatile portfolios and expect lower returns than men do.

Studies about women investors tend to show that their cautious nature can help them outshine men, but those results are generally calculated on a risk-adjusted basis. What that means is that while women may be getting good results based on the low-risk investments they choose, their risk avoidance may also be causing them to leave money on the table.

4. They're Less Confident

In survey after survey, women rate themselves as less confident, less knowledgeable and generally less capable in finance than men do. That can often leave women sitting on the sidelines or choosing investments that put safety above growth.

The National Center for Retirement Research estimates that 80 to 90% of women will be solely responsible for their finances at some point in their lives. Fewer than 20% feel prepared to make wise financial decisions.

5. They're Often Overlooked

Several studies suggest that the financial industry has a poor track record when it comes to serving women. According to a survey by Boston Consulting Group, more than 70% of women are dissatisfied with the financial services industry and feel that their gender affects not only the quality of advice they receive, but whether they're taken seriously.

So what do women want from their advisors? More information -- and more respect. Unfortunately, many women report that their opinions on financial matters are not taken as seriously as men's, according to a BMO Nesbitt Burns survey conducted in 2012. This leaves women in a bit of a catch-22 in terms of getting on top of their financial affairs.

Women and Retirement Savings

Saving for retirement is a challenge, but the situation is particularly complex for women, who face specific hurdles that threaten their ability to save. That said, these additional challenges are no excuse for post-work pennilessness.

When it comes to preparing for retirement, the process is the same for both men and women: Plan carefully, save diligently and invest intelligently. Extenuating circumstances aside, that's the best anyone can do.

Also from GoBankingRates.com: Women and Debt: Ditch the Credit Card to Start Saving for Retirement

Tara Struyk is a reporter for GoBankingRates.com.

This article was originally posted at GoBankingRates.com:
5 Reasons Why Women Have to Work a Lot Harder at Retirement Savings