Women face unique challenges when preparing, according to a recent study.

Researchers at American University found that retirement-age women who have new grandchildren are 9 percent more likely to retire early than those do not.

According to researchers, the increased probability of early retirement due to the arrival of grandchildren is comparable to the number of women that retire due to worsening health. The decision to retire early has a significant impact on income adequacy later in life as it can result in lower IRA, Social Security and pension benefit amounts.

As reported in a recent Bloomberg article, "the large Baby Boom generation puts a big strain on the budgets of Social Security, Medicare and other retirement programs. One way to lower costs is to require Americans work longer before getting those benefits."

For the study, examined the retirement choices made by more than 47,400 retirement-age women and found that many retire early to care for their grandchildren. Early retirement poses a particular threat for women who often have had both lower earnings and fewer years in the labor force than men and consequently receive lower income during their retirement years.

According to the study, policies that address childcare needs of younger generations could help to reduce care demands on those of retirement age and hence keep the older generation in the workforce longer.

Additionally, the research notes that those women who have access to flexible work arrangements (such as reducing the number of hours they work) are less likely to retire, indicating a desire to continue working. It remains unclear as to whether women leave work to care for grandchildren out of necessity or out of choice, researcher Robin Lumsdaine noted.

The findings are detailed in the journal Demography.