She'll take limited time off because she is superhuman.

Hiring some additions to her team.
Hiring some additions to her team.
(via Getty)

Marissa Mayer said that she's pregnant with identical twin girls via her Tumblr account, a very fitting way to deliver the announcement from a Silicon Valley leader. As an engineer and computer nerd, she of course found a way to include some math with the good news:

"The twins part was quite a surprise, because I have no family history of twins or any other predisposing factors.  However, as I’ve now learned, identical twins occur by random chance in roughly 1 out of approximately every 300 pregnancies.  Zack and I have embraced the surprise and are very excited about these new additions to our family."  

Sources: Tumblr