(Reuters) - A sales representative for Merck & Co. filed a more than $100 million sex discrimination lawsuit against the drugmaker on Thursday, claiming that it particularly discriminates against pregnant employees and women with children.

The plaintiff, Kelli Smith, in a lawsuit filed in U.S. District Court in New Jersey, claims she was demoted for taking maternity leave in 2010, and penalized by unfair performance evaluations and other actions that stalled her career and hurt her reputation.

The lawsuit, which seeks class-action status, alleges the No. 2 U.S. drugmaker engages in "systematic, companywide discriminatory treatment of its female employees on the basis of their gender and their taking federal and state-protected pregnancy leave."

Smith is described in the lawsuit as a senior sales rep in Merck's Toms River, New Jersey, district, who has been a top performer in terms of sales.

Smith was hired by Merck in 2004.

Merck officials could not be reached immediately for comment.

The lawsuit claims that Merck's companywide sales incentive plan "provides that the compensation of managers and directors is decreased when their employees take legally protected leave. ... Through this centralized policy, Merck discourages management from hiring and promoting women."

Smith is represented by the law firm of Sanford Heisler, which won a May 2010 lawsuit that made similar claims against Swiss drugmaker Novartis AG .

Novartis was ordered to pay $250 million in punitive damages after a federal jury in Manhattan found the company had discriminated against thousands of female sales reps in terms of pay, promotions and pregnancy policies.

Following subsequent negotiations, Novartis reached a final settlement that provided $175 million to its 6,200 affected female employees.

Shares of Merck were up 0.2 percent to $45.09 in midday trading on the New York Stock Exchange.

The case is Kelli Smith, individually and on behalf of a class of similarly situated female employees, vs Merck & Co Case No: 3:33-av-00001

(Reporting by Ransdell Pierson; editing by John Wallace and Leslie Adler)

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