When Heather Wiseman began to suffer from bladder infections as a result of her pregnancy, the Walmart sales associate started carrying a water bottle during the day to stay hydrated. But the Walmart that employed Wiseman technically allowed only cashiers to have water bottles, and a note from Wiseman's doctor made no difference. Caught with a water bottle again, the pregnant Wiseman was fired from her job in 2007 for insubordination based on her failure to follow the water bottle rule.

Another woman, Victoria Seredny, was told not to move heavy objects -- something she did a few minutes a day in her job as a nursing home activities director -- by her doctor after a near-miscarriage. When she asked for help, she said her boss refused to allow her colleagues to assist her, even those who volunteered. Serendy was fired soon after for failure to perform her duties.

Both Wiseman and Serendy sued their employers for wrongful termination, and both of them lost their cases. But legislation recently introduced in the Senate could help to prevent situations like this from happening.

The Pregnant Workers Fairness Act (PWFA), introduced Friday by Sen. Jean Shaheen (D-N.H.) and Sen. Bob Casey (D-Pa.), would require employers to make the same kind of workplace accommodations for pregnant women that current law requires them to make for people with disabilities.

Under the Americans with Disabilities Act (ADA), these are called "reasonable accommodations," designed so that employees with disabilities can perform the job functions they were hired to do.

Pregnancy, however, is not considered a disability. Instead, pregnant women are protected by the 1978 Pregnancy Discrimination Act, which makes it illegal to fire a woman just because she becomes pregnant. But employers can still refuse to accommodate pregnant women's basic, temporary medical needs at work, like Wiseman's request for a water bottle, essentially forcing them to choose between keeping their job and ensuring the health of their unborn child and themselves.

“As more and more women are working longer into their pregnancies, they deserve reasonable accommodations to maintain their safety and health,” Sen. Shaheen said in a statement, adding that the bill would allow women "to work longer and more productively at their jobs while also providing for their families and helping strengthen our economy."

Women make up approximately half of the U.S. labor force, which includes more than 77 million working women, according to the National Women's Law Center (NWLC). Ensuring these women have the opportunity to work well into the third trimester of a pregnancy can be crucial for their families, and even more so for those women in hourly, low-wage jobs. In 2010, 41 percent of working mothers were their family’s primary breadwinner.

A version of the Pregnant Workers Fairness Act was introduced in the House of Representatives this spring by New York Rep. Jerry Nadler (D-N.Y.). It currently has 109 co-sponsors, all of them Democrats. But even with the added step of the newly-introduced Senate legislation, the bill's chances of passage remain slim.

The Republican-controlled House has consistently opposed workplace bills like PWFA, which they argue place an unnecessary burden on businesses, lowering overall profits. The Senate is similarly inclined. Earlier this year, all 47 Senate Republicans voted to block a bill called the Paycheck Fairness Act, which would have facilitated the monitoring of gender disparities in pay, and would have protected employees who ask about pay discrepancies from retaliation. Women in the U.S. currently make about 77 cents for every dollar that men earn.

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