Women have faced gender discrimination at work since, oh, forever. Still, many have forged ahead and proven themselves leaders, like fashion industry leader Donna Karan.

Still, in addition to outright discrimination, women face additional challenges, not the least of which is in the choice to become a parent. In addition to society's expectation to be the primary caregiver, they often have to slow down their career path or instead delay having children.

According to a new study in the American Journal of Public Health, waiting may offer a significant benefit: a longer life. Researchers at the University of California, San Diego found that the odds of living until at least 90 increased when women waited to have a first child.

The study is based on a "multiethnic cohort of postmenopausal US women in the Women's Health Initiative recruited from 1993 to 1998 and followed through August 29, 2014." The researchers followed the women for up to 21 years and took into account demographic, lifestyle, reproductive, and health-related factors. Of the 20, 248 women in the study, 54 percent lived until 90.

Later in life is a relative term in the study, which split the group into women under 25 years of age and those 25 and older. Those who were first-time mothers in the older group had a roughly 21 percent greater chance of reaching 90.

Also, those who had two to four pregnancies that went to term were even more likely to live until 90.

The trick with studies such as this is to understand the difference between a correlation and cause. Other factors than age were also more common among women who lived longer, including college matriculation, marriage, higher income, and lower likelihood of obesity or a history of chronic disease. As a university press release about the study quoted Aladdin Shadyab, PhD, lead author and a postdoctoral fellow with the Department of Family Medicine and Public Health at UC San Diego School of Medicine:

Our findings do not suggest that women should delay having a child, as the risk of obstetric complications, including gestational diabetes and hypertension, is higher with older maternal ages. It is possible that surviving a pregnancy at an older age may be an indicator of good overall health, and as a result, a higher likelihood of longevity. It is also possible that women who were older when they had their first child were of a higher social and economic status, and therefore, were more likely to live longer.

Potential pregnancy complications increase with the age of the mother, so to delay too long could raise other problems. However, establishing yourself, creating a better income, and providing opportunities for better healthcare all make sense, whether you have a child or not.