The Civil Rights Act of 1964 protects you from discrimination in the workplace on account of sex, race, religion, etc. In 1978, Congress passed the Pregnancy Discrimination Act, which amends the Civil Rights Act to explicitly identify employers’ responsibilities to protect the rights of employees who are or may become pregnant.
Under the Pregnancy Discrimination Act, it is a violation of your civil rights for an employer to fire or refuse to hire you on the basis of a current pregnancy or plan to become pregnant in the future. According to Chron.com, your employer cannot prevent you from doing your job as long as you are able and must treat you the same as non-pregnant co-workers. Here are some of your specific rights under the Act.
When you are on maternity leave after the birth of your child, your employer must save your position for you, just as for an employee on short-term disability. You must also receive the same benefits as you would otherwise and accrue vacation pay, seniority, etc. while on maternity leave.
Your employer does not necessarily have to provide you with health insurance but cannot deny you such a benefit specifically because you are pregnant. Your employer cannot charge you higher deductibles related to your pregnancy, and you must receive the same coverage as your co-workers.
Pregnancy discrimination is a specific form of sex discrimination. Therefore, the Pregnancy Discrimination Act did not make it illegal for your employer to treat you unfairly because of your pregnancy. Rather, it explained specifically why it was illegal under the existing law.