Pregnancy discrimination occurs when expectant women are fired, not hired, or otherwise discriminated against due to their pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

 or intention to become pregnant. Common forms of pregnancy discrimination include not being hired due to visible pregnancy or likelihood of becoming pregnant, being fired after informing an employer of one’s pregnancy, being fired after maternity leave, and receiving a pay dock due to pregnancy.
Employers discriminate on the grounds of pregnancy for a number of reasons:

• prejudice
  Prejudice
  Prejudice is making a judgment or assumption about someone or something before having enough knowledge to be able to do so with guaranteed accuracy, or "judging a book by its cover"...
  
  s against working women and mother
  Mother
  A mother, mum, mom, momma, or mama is a woman who has raised a child, given birth to a child, and/or supplied the ovum that grew into a child. Because of the complexity and differences of a mother's social, cultural, and religious definitions and roles, it is challenging to specify a universally...
  
  s
• fear of loss of productivity due to the absence of an employee
• insufficient resources to support temporary employees or provide overtime pay for other employees to fulfill the duties during leave
• belief that the employee will require too many accommodations even after her return.

In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, since 1978, employers are legally bound to provide the same insurance

Insurance

In law and economics, insurance is a form of risk management primarily used to hedge against the risk of a contingent, uncertain loss. Insurance is defined as the equitable transfer of the risk of a loss, from one entity to another, in exchange for payment. An insurer is a company selling the...

, leave pay, and additional support that would be bestowed upon any employee with medical leave or disability.