Yes, through a break in service. The current rules on breaks in service are as follows:
Different rules apply with respect to breaks in service prior to 1986. Effective January 1, 1989, once you have accumulated at least five (5) years of Vesting Service (except for years of vesting service that are not taken into account because of a break in service), your benefit is non-forfeitable, and your credit cannot be cancelled.
Parental leave. Effective January 1, 1985, you will not have a one-year break in service if you leave work because of pregnancy, childbirth, adoption, or infant care. While you are not working for these reasons, you will receive credit for a maximum of 501 hours of service. This credit only prevents a break in service. It does not count toward Future Service or Vesting credit.
This break-in-service protection will apply to either:
Here is an example of when you receive break-in-service protection for a parental leave:
Suppose Mary's credit year starts January 1 and ends December 31. In 2009, Mary completes 380 hours of service as of March 31. On April 1, she leaves work for the rest of the credit year and the following credit year to care for a child she adopted. Mary will receive credit for enough hours of service so that she will have a total of 501 hours of service for 2010. Mary does not have a one-year break in service because in 2009 or 2010, she was credited with at least 190 hours of service (see above).