Having children is one of life’s most rewarding experiences—but it’s not a cheap one.

An American family with a six-figure annual income can expect to spend nearly $408,000, on average, by the time a child born in 2013 turns 18, according to the latest annual Expenditures on Children by Families report from the U.S. Department of Agriculture. Because that figure is not adjusted for inflation, families can expect true per-child costs to reach over half a million dollars.

For many women, however, the true cost of having children is more than just the dollars spent on raising children. It’s also the career sacrifices that many women make to raise children. Research shows that even short career breaks of less than two or three years can have large financial implications.

A 2005 Harvard University study found that 43 percent of “highly qualified” professional women with children chose to take time off from their careers. They took off an average of 2.2 years. (A shorter follow-up survey by Harvard in 2010 found similar results.)

The study found that such “off-ramping” decreases a woman’s earning power by an average of 18 percent, and as much as 28 percent if she works in the business sector.

“The longer [women] spend out, the more severe the penalty becomes,” says the article in the Harvard Business Review. “Across sectors, women lose a staggering 37 percent of their earning power when they spend three or more years out of the workforce.”
 
So, how can women reduce the effects of career breaks on their professional prospects and income?

Sallie Krawcheck, a well-known former banking executive and owner of Ellevate, a global network for professional women, says it’s important for women to consider the implications of even short career breaks. While companies should do more to help women balance their work lives with their professional lives without the career penalties, women can also take better charge of the situation.

Here are some of the tips Krawcheck recommends:

Find the right employer. Aim to work for a company that has shown itself to promote women into executive ranks and that offers some flexibility to women with children. “Actively seek out employers where the workplace culture is one of flexibility without shame,” Krawcheck says. “What I mean by that is, choose companies that are known for giving both women and men flexibility in their work lives and for promoting women into leadership positions.” (Krawcheck is a trustee of a mutual fund called the Pax Ellevate Global Women’s Index Fund that invests in companies with a significant portion of women among their executive ranks.)

Know the potential cost of a career break. Before embarking on a career break, it’s important to understand the financial sacrifices you may be making. Consider how a break might affect your long-term career and income prospects. “Consider not only the salary hit you might face by taking a break, but also take into account the raises and promotions you may not get in the future,” Krawcheck recommends. “It’s important to know what you might be giving up.”

Also consider meeting with a financial advisor to help you evaluate how to adjust your financial plan to accommodate for any career break and build a plan that helps you more effectively manage the costs of motherhood.