The Pregnancy Discrimination Act, 42 US Code Chapter 21 Sec. 701 (k) of Civil Rights Act of 1964 Title VII

(k) The terms "because of sex" or "on the basis of sex" include, but are not limited to, because of or on the basis of pregnancy, childbirth, or related medical conditions; and women affected by pregnancy, childbirth, or related medical conditions shall be treated the same for all employment-related purposes, including receipt of benefits under fringe benefit programs, as other persons not so affected but similar in their ability or inability to work, and nothing in section 2000e-2(h) of this title shall be interpreted to permit otherwise. This subsection shall not require an employer to pay for health insurance benefits for abortion, except where the life of the mother would be endangered if the fetus were carried to term, or except where medical complications have arisen from an abortion: Provided, That nothing herein shall preclude an employer from providing abortion benefits or otherwise affect bargaining agreements in regard to abortion.