Chelsea Clinton gave birth to a daughter late Friday, the former first daughter announced on her official Twitter feed and Facebook page.
The girl, Charlotte Clinton Mezvinsky, is the first grandchild of former President Clinton and first lady Hillary Clinton.
Clinton spokesman Kamyl Bazbaz said the child was born on Friday but did not immediately provide additional details. The couple lives in New York City.
The baby arrives as Hillary Clinton deliberates on whether to seek the White House in 2016, a decision that could put her on a path to becoming the nation's first female president. Clinton is the leading Democratic contender to succeed President Barack Obama, her former 2008 campaign rival, and has said she expects to make a decision around the beginning of next year.
The baby has been eagerly anticipated as Hillary Clinton considers her political future — she has called the prospect of becoming a grandmother her "most exciting title yet." She even has picked out the first book she intends to read to her grandchild, the classic "Goodnight Moon."
She has said she didn't want to make any decisions about another campaign until the baby's arrival, pointing to her interest in enjoying becoming a grandmother for the first time. If Clinton decides to run for president, her campaign would coincide with the baby's first two years.
The former president has been eager to become a grandfather. During an event with former President George W. Bush in September, Mr. Clinton's cell phone rang on stage and he joked that only two people had the number "and they are related to me," musing that he hoped he wasn't becoming "a premature grandfather."
"Every day I get up and I say, 'You have to remember whose child this is. Do not interfere. Be there when you are welcome. Be loving but not judgmental," Clinton said to laughs in an interview with CNN at his annual Clinton Global Initiative, only days before the baby's arrival.
Even Obama got into the act. Addressing the annual Clinton confab, Obama quipped if Chelsea Clinton went into labor during his speech, "she has my motorcade and will be able to navigate traffic."
The 34-year-old Chelsea Clinton said in an interview with Glamour magazine last year that she and her husband had hoped to make 2014 "the year of the baby." She announced her pregnancy in April at the end of a forum in New York on female empowerment.
Chelsea Clinton grew up in the public eye as a teenager in the White House, later graduating from Stanford and Columbia universities. She worked in finance in New York and in public health, earning a doctorate from Oxford University while taking on a prominent role as vice chair of her family's foundation. She recently departed NBC News, where she served as a special correspondent.
The new parents, who married in 2010, were friends as teenagers in Washington and both attended Stanford. Mezvinsky is a hedge fund manager and the son of former Reps. Majorie Margolies of Pennsylvania and Edward Mezvinsky of Iowa, longtime friends of the Clintons.
The Associated Press contributed to this report.