Yahoo Inc Chief Executive Marissa Mayer . (REUTERS/Pascal Lauener)

Yahoo chief executive Marissa Mayer is expecting twins, but she barely plans to take maternity leave.

"Since my pregnancy has been healthy and uncomplicated and 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," she wrote in Tumblr post. "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 was pregnant when Yahoo first poached her from Google in 2012 and took two weeks off after the birth of her son. The length of the leave drew criticism from some for setting unrealistic expectations -- as did a clamp down on remote work at Yahoo, a policy that some argued made work-life balance harder for some employees.

[Marissa Mayer is pregnant again, this time with twin girls. Now let’s move on.]

From a business perspective, Mayer's decision makes sense: Yahoo remains in a sensitive position and executives make sacrifices for their businesses. Her decision about how to treat working and her pregnancy is her own to make -- and it's undoubtedly based on a variety of business and personal factors no one but she can judge.

But it's hard not wonder if Mayer's quickness to come back to work could make some female employees think twice about taking their full maternity time, lest they appear less than dedicated. And surely not all of them are able to have the sort of resources or support system to make coming back to work so quickly feasible: Mayer reportedly paid for a nursery to be built next to her office after her son's birth.

This line of questioning is uncomfortable for a number of reasons: For one, a male executive with an expanding family likely wouldn't face the same scrutiny. And secondly, despite being one of the most prominent women in the tech, Mayer has seemed less than comfortable being held up as an example when it comes to tech and gender. In fact, she's downplayed Silicon Valley's women problem in the past.

"In technology we live at a rare, fast-moving pace," she said an interview with BackChannel earlier this year. "There are probably industries where gender is more of an issue, but our industry is not one where I think that’s relevant."

Yet by sheer timing, it seems inevitable that Mayer's pregnancy will play into a larger debate about parenthood and Silicon Valley's work expectations.  Maternity and paternity leave have been a hot topic in recent months, with Netflix, Adobe and Microsoft all announcing increasingly generous leave packages for new parents.

And other tech companies have found that these benefits are important for keeping women on board. A few years ago, Google found that the women who had recently given birth were twice as likely as other employees to leave the company -- so they extended their maternity leave time and switched it from partial to full pay. "Attrition decreased by 50 percent," the New York Times reported in 2012.

Given that tech company diversity report after diversity report has found that women are under-represented among Silicon Valley's biggest names, parental leave is likely to continue to be a major topic for discussion -- whether that means thinking through policies that help women come back to their jobs or by encouraging men to "lean out" and take their full paternity allotment to help level the playing field.