Your employer sounds like a real mean guy. I would check out the EEOC website. Here is what I found about pregnancy. You also may want to contact an employment lawyer (www.targetlaw.com)

Pregnancy Discrimination
The Pregnancy Discrimination Act is an amendment to Title VII of the Civil Rights Act of 1964. Discrimination on the basis of pregnancy, childbirth, or related medical conditions constitutes unlawful sex discrimination under Title VII, which covers employers with 15 or more employees, including state and local governments. Title VII also applies to employment agencies and to labor organizations, as well as to the federal government. Women who are pregnant or affected by related conditions must be treated in the same manner as other applicants or employees with similar abilities or limitations.

Title VII’s pregnancy-related protections include:

Hiring
An employer cannot refuse to hire a pregnant woman because of her pregnancy, because of a pregnancy-related condition or because of the prejudices of co-workers, clients, or customers.

Pregnancy and Maternity Leave
An employer may not single out pregnancy-related conditions for special procedures to determine an employee’s ability to work. However, if an employer requires its employees to submit a doctor’s statement concerning their inability to work before granting leave or paying sick benefits, the employer may require employees affected by pregnancy-related conditions to submit such statements.

If an employee is temporarily unable to perform her job due to pregnancy, the employer must treat her the same as any other temporarily disabled employee. For example, if the employer allows temporarily disabled employees to modify tasks, perform alternative assignments or take disability leave or leave without pay, the employer also must allow an employee who is temporarily disabled due to pregnancy to do the same.

Pregnant employees must be permitted to work as long as they are able to perform their jobs. If an employee has been absent from work as a result of a pregnancy-related condition and recovers, her employer may not require her to remain on leave until the baby’s birth. An employer also may not have a rule that prohibits an employee from returning to work for a predetermined length of time after childbirth.

Employers must hold open a job for a pregnancy-related absence the same length of time jobs are held open for employees on sick or disability leave.

http://www.eeoc.gov/types/pregnancy.html