The syndrome is nothing new. As early as 1993, the American College of Sports Medicine warned about the reproductive fallout of excessive exercise in women.
It noted that recreational jogging -- only 12 to 18 miles a week -- can result in poor follicular development, decreased estrogen and progesterone secretion and absent ovulation.
Reproductive specialists say they see amenorrhea most frequently in ballet dancers and long-distance runners. Some studies have shown 44 percent of all ballet dancers have no periods.
But it's also a problem in college athletes.
Katlyn Haycock, a 20-year-old exercise science major and former Syracuse University Women's tennis team player, has experienced amenorrhea and low estrogen levels.
"It started happening in high school," she said. "I was working out too much and my body didn't have enough energy to maintain it."
"Freshman year I never took days off except for Christmas and Easter," said Haycock. "I started overtraining definitely during my freshman year, and it continued in my sophomore year. And then I started to burn out."
She said she has never worried about her lack of periods or her fertility.
"It's a little more convenient with playing a sport, you didn't have to worry about it," she said. "It honestly didn't bother me too much."
Estrogen is an essential protective hormone for women and long-term data show an impact on cardiovascular health, according to Dr. Wendy Chang, a reproductive endocrinologist at the Southern California Reproductive Center in Beverly Hills.
"I think the bigger issue, more than the health consequences now, are that women who have exercise-induced amenorrhea have decreased bone density," said Chang. "And even though they are belly-dancers and doing weight-bearing exercises, they are more prone to stress fractures."
But the biggest factor in infertility is age, when female athletes delay childbearing for their careers.
Many women delay having children, and as a result, 20 percent of all women in the U.S. have their first child after 35, according to the RESOLVE, the National Infertility Association.
"We peak at 25," said Chang. "A woman in her early 20s has a 30 percent chance of getting pregnant. That drops to 12 to 13 percent at 35 and by 40, it's 5 percent."
Some specialists, including Chang, recommend that women who intend to devote their childbearing years to professional sports consider freezing their eggs when they are at their peak in their 20s.
"Pregnancy rates five years ago were in the 3 percent range," said Chang. "Nowadays vitrification techniques have significantly improved egg survival and pregnancy rates and studies suggest that if you freeze eggs under age 35, pregnancy rates improve."
"The best quality eggs are in 20-year-olds," she said. "They should consider it as long as they have a balanced and detailed discussion with a reproductive endocrinologist about the risks and benefits. Armed with good information, it's a good option for women."
As for Sarah Joyce, she hopes to soon resume running with her newborn Makayla in her new running stroller.
But she is more cautious about her health than ever before.