Serena Williams reveals 'whole new kind of fear' during daughter's birth

The five-part documentary opens with the revelation that Williams was pregnant last year when she won her 23rd Grand Slam title. Her husband, internet entrepreneur Alexis Ohanian, says she did not drop a single set during the Australian Open because she was in a rush to get off the court.

"She was looking out for the baby," he jokes.

The documentary chronicles Williams' experience getting married and becoming a mother, along with the challenges she faced with the birth of their daughter, Alexis Olympia, in September. Williams, 36, says thinking about that episode brings her to tears.

Here are other highlights from the documentary's first installment:

Finding love and getting married

"For so many years, I defined myself in just one way: by success, by championships, by making history. And then, all of the sudden, my life changed forever," Williams said. "It wasn't part of any plan to have this happen, not while I was still on top. But two years ago, I met this man, almost out of nowhere. We fell in love."

Complications from giving birth

Williams and Ohanian welcomed their daughter on September 1 by C-section, which she had hoped to avoid because of her history of blood clots.

Then, chaos struck.

"One minute, everything's going according to plan, and then I'm being wheeled off for surgery. I was terrified. It was a whole new kind of fear," she says in the documentary.

What followed were six days of uncertainty, Williams wrote in February in an essay for CNN detailing her birth complications.

"First my C-section wound popped open due to the intense coughing I endured as a result of the embolism. I returned to surgery, where the doctors found a large hematoma, a swelling of clotted blood, in my abdomen. And then I returned to the operating room for a procedure that prevents clots from traveling to my lung. When I finally made it home to my family, I had to spend the first six weeks of motherhood in bed."

In the documentary, Williams says, "I can't believe how much went wrong on my way to meeting her. I almost died. ... But now, she's the reason why this all means even more than it did before."

Role as a first-time mom

"Becoming a mom, I definitely feel the pressure, and I feel a little anxiety," she says. "Am I going to be a good mom, a strict mom, not strict enough? I don't really know, so that anxiety has turned into nervousness and fear. ... It's the same attitude I have in tennis."

Returning to tennis

"There's no escaping the fear -- the fear that I might not come back as strong as I was, the fear that I can't be both the best mother and the best tennis player in the world," she says. "I guess my only choice is to live and find out."

The documentary

"It documents my pregnancy, the extremely difficult time I had in the delivery room and all of the emotions that came with it," Williams says of the TV series. "It also covers my wedding, which was so exciting and fun. It was honestly the best day of my life. And then of course, it shows my comeback, because I'm coming back, I'm playing tennis, I'm back on the court, and it's so invigorating."

The rest of the series will air this month.