Women who take charge, do the math, plan for contingencies and work with their partners and/or financial advisors have a better chance of securing their finances in retirement than those who shrink from the process, according to a new study.

The MetLife Study of Women, Retirement, and the Extra-Long Life: Implications for Planning shows women face a number of unique financial risks-including outliving retirement funds, aging single, lower retirement incomes, greater health care costs and added care-giving responsibilities-and have not planned adequately to address these concerns.

The study examines the thinking and practices of mature women, ages 50 to 70, in the context of the "extra" challenges they may experience in retirement. According to the report, women expect to live until age 85, some until age 90, and are more concerned than men about the costs of health care and long-term care and outliving their assets.

Slightly more than half of the women surveyed know the likely amount of their retirement income/assets and only 44% have calculated the amount of their essential expenses, according to the study. Approximately one-in-six (16%) reported that they have or plan to delay retirement, on average, four years.

The data suggests that women who work collaboratively with spouses, partners, financial advisors and even knowledgeable friends, report higher confidence in their retirement security. Among men and women, men are more likely, by a margin of  65% to 55%, to calculate retirement income.

"The combination of risks for women and their relatively inadequate retirement planning has become known as the 'perilous paradox,' but the message is clear that women are able to avoid that," said Sandra Timmermann, director of the MetLife Mature Market Institute. "The risks and costs of 'living long and living female' call for an 'affirmative action' plan. We find that those who plan for a steady stream of income, along with some flexibility for the unexpected, are best prepared for what can be an extended future."

Longer life spans for American women-who live longer than men, on average-creates additional costs and financial constraints that can lead to greater financial challenges in retirement, according to the study. As of 2009, women aged 65 years or older had significantly lower annual retirement incomes than men-an average of $21,500 vs. $37,500. American women are more likely to experience retirement alone since many never marry or are widowed or divorced.

More than half of the women, 54% compared to 44% of men, report that they are very or somewhat concerned about outliving their retirement resources, according to the study. Of women who were at least somewhat confident about their ability to live comfortably in retirement, 66% attributed this to having a guaranteed stream of income. Of those not confident, 61% said they lacked sufficient savings to last their anticipated lifetime.