Marissa Mayer
Yahoo CEO Marissa Mayer smiles before the session, "In Tech We Trust," in the Swiss mountain resort of Davos, on Jan. 22, 2015. Reuters/Ruben Sprich

Marissa Mayer, the Yahoo Inc. chief executive, will soon have two new reasons to take some time away from work. Mayer announced Tuesday that she is pregnant with identical twin girls and is due to give birth in December.

But that’s unlikely to slow her down much at work. Mayer, 40, said she is going to limit the amount of leave she takes following delivery, as she did with her first child.

"Since this is a unique time in Yahoo's transformation, I plan to approach the pregnancy and delivery as I did with my son three years ago, taking limited time away and working throughout," Mayer wrote on Yahoo’s corporate blog Tuesday. “I’ve shared the news and my plans with Yahoo’s board of directors and my executive team, and they are incredibly supportive and happy for me.”

Mayer's pregnancy announcement comes as Yahoo prepares to spin off its stake in Alibaba Group Holding Ltd, the Chinese e-commerce giant, and considers what to do with its holdings in Yahoo Japan Corp., according to a Reuters report. The announcement also is likely to renew a debate about leave for new parents and the status of women in the workplace.

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Yahoo said in its corporate blog Tuesday that it was "extremely happy" for Mayer and supports her approach to taking maternity leave.

Mayer was pregnant when she joined Yahoo as CEO in 2012 and gave birth to a boy in September of that year, Reuters reported. She worked from home after the birth and was back in office after being away for two weeks.

In an effort to boost employee morale at the nearly 20-year-old Internet company, Mayer increased the amount of paid leave offered to new parents in 2013. The policy change allowed new mothers to take up to 16 weeks of paid time off and fathers eight. However, a ban on employees working from home in the same year angered many. Critics said the policy would actually make life more difficult for working parents.