The 2017 Serena Williams tennis season officially began on 5 January with the start of the 2017 ASB Classic. Williams entered the season as the number two ranked player. On January 28, 2017, Williams set a record for the most slams in the Open Era when she claimed her 23rd slam at the 2017 Australian Open. On April 19, she announced that she was pregnant with her first child and would not participate in any further tournaments for the rest of the year.