Seventy percent of mothers with children under the age of 18 are in today's workforce, according to the U.S. Department of Labor. In a tight labor market, it's a great time for companies to focus on creating work environments that empower working parents. Each year, Working Mother magazine releases a list of the 100 Best Companies for working mothers. To make the cut, companies submit an application that includes more than 400 questions about leave policies, workforce representation, benefits, childcare assistance, advancement programs and flexibility. The application also inquires about whether employees are actually taking advantage of a company's benefits. "That all of these programs and policies are offered is just half of it," Working Mother President Subha Barry tells CNBC Make It. "The other half is that you encourage people to use it, and don't penalize them."

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Working Mother presents this list as a group of 100 companies, without assigning specific rankings to any of the companies with the exception of No. 1. They also identify the group of companies that fall in the top 10, which are presented here in alphabetical order. Barry praises Unilever for earning the top spot this year. Fifty-two percent of the company's managers are women, and Unilever offers paid maternity and paternity leave as well as paid adoption leave. The consumer goods company also offers employee reimbursement on in vitro fertilization and other fertility treatments. Also of note: Not all of these companies offer substantial maternity leave benefits. WellStar Health System offers just three weeks of paid maternity leave, while most of the companies in this group offer at least 16 weeks. However, with fertility benefits and a high percentage of women employees and women managers, Working Mother still placed WellStar Health System among its best 10 companies. Check out the 10 best companies for working mothers:

1. Unilever

Percentage of employees who are women: 44 percent

Percentage of managers who are women: 52 percent

Paid maternity leave offered: 16 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 49 percent (Remaining companies in the top 10 presented in alphabetical order)

AbbVie

Percentage of employees who are women: 53 percent

Percentage of managers who are women: 57 percent

Paid maternity leave offered: 14 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 94 percent

Deloitte

Percentage of employees who are women: 43 percent

Percentage of managers who are women: 43 percent

Paid maternity leave offered: 22 weeks offered

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 95 percent

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Ernst & Young LLP

Percentage of employees who are women: 45 percent

Percentage of managers who are women: 47 percent

Paid maternity leave offered: 16 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 95 percent

IBM

Percentage of employees who are women: n/a

Percentage of managers who are women: n/a

Paid maternity leave offered: up to 20 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: n/a

Johnson & Johnson

Percentage of employees who are women: 45 percent

Percentage of managers who are women: 46 percent

Paid maternity leave offered: 15 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 75 percent

A job seeker talks to a Johnson & Johnson job recruiter at a career fair in Washington, D.C. Andrew Harrer | Bloomberg | Getty Images

McKinsey & Company

Percentage of employees who are women: 46 percent

Percentage of managers who are women: 45 percent

Paid maternity leave offered: 16 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 100 percent

Moody's

Percentage of employees who are women: 40 percent

Percentage of managers who are women: 38 percent

Paid maternity leave offered: 16 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 95 percent

Proctor & Gamble

Percentage of employees who are women: 36 percent

Percentage of managers who are women: 42 percent

Paid maternity leave offered: 16 weeks

Reimbursement on in vitro fertilization: yes

Percentage of workforce that has the option to telecommute: 80 percent

WellStar Health System