But South Korean Amy Yang pushed herself into contention with a brilliant nine-under-par round of 61, leaving her in second place alongside American Lilia Vu, who shot 62.
The event is named after Swedish legend Annika Sorenstam, who won 72 LPGA titles, including 10 major crowns, and has attracted a strong field to the Pelican Golf Club in Belleair, Florida.
After rounds of 63 and 65, Pedersen maintained her consistency with a bogey-free round, gaining momentum with birdies on the second and third holes.
But she turned on the style on the back nine with four birdies, including on the par-4 18th.
"Pretty solid today. Was my first day without a bogey. I think I hit it really well. I had a lot of chances. Felt like I missed quite a few birdie putts out there," said the Copenhagen native.
"My short game was pretty good today. I got up and down every time I missed a green, and I holed a chip, so that definitely kept me in the game, especially early in the round," she added.
But the round of the day came from Yang, who made seven birdies plus an eagle on par-4 fourth where she holed out from the fairway.
"Had a great driver, middle of the fairway. I had about 120 yards slightly into the wind. Hit a 9-iron, just soft 9-iron, one bounce in. It was great to see. Yeah, it was fun," she said.
The 34-year-old Yang has claimed four career victories on the LPGA Tour but has yet to win in the United States.
Vu is in contention for the LPGA Player of the Year, sitting three points behind leader Celine Boutier of France, who missed the cut.
The LPGA season concludes next week with the Tour Championship in Naples, Florida.
The 26-year-old Californian started and ended her round with birdies, making eight in total as she targets her fourth win on Tour this season.
Vu triumphed in the Honda LPGA Thailand, the Chevron Championship and the Women's Open and she said it was the latter victory that gave her thoughts of winning the Player of the Year.
"It wasn't until after the Open I started thinking about it. Then started thinking about it, started playing worse, so now I don't think about it. I just try to play well. It's just balance," she said.
"It would mean almost too much. I think this year has been phenomenal for me, more than I expected. Last year was really hard on myself, and then from before, just being on the Epson Tour and just thinking about not even playing anymore, I think I'm glad I didn't give up and I'm here now," she said.
Four players are five shots off the lead - American Alison Lee and Thailand's Patty Tavatanakit, who both shot 62, Spain's Azahara Munoz and Mexican Gaby Lopez.
Japan's Minami Katsu, who had started the day two shots behind Pedersen, slipped four shots further back. She had to settle for 68 after a triple bogey on the opening hole.
