Serena Williams will go on maternity leave after she welcomes her baby and will take some time off from tennis until 2018, a representative told reporters. Serena posted on her Snapchat Wednesday a selfie of her showcasing a baby bump, with the caption "20 weeks." She is engaged to the social network's co-founder Alexis Ohanian. Her rep confirmed to E! News Serena is pregnant and due to give birth this fall.