Sasha Pieterse starred as Alison DiLaurentis on the hit show 'Pretty Little Liars'
"Pretty Little Liars" quickly became one of the most talked about shows on television when it premiered in 2010.
Actress Sasha Pieterse was only 13 when she started playing the presumably murdered, 15-year-old "queen-bee" Alison DiLaurentis. A few years later, she would start to notice changes in her health, particularly her metabolism.
"The changes that were happening to me were documented on camera…At 17, I gained 70 pounds in the year…for no reason… There was no explanation for it," she revealed on the "The Squeeze" podcast with actor Taylor Lautner and his wife, also Taylor Lautner.
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Sasha Pieterse says it was hard being on a such a wildly successful television show in "Pretty Little Liars" when she was a teenager due to health changes. (Albert L. Ortega/VALERIE MACON/David Livingston/Getty Images)
"I went to over 15 gynecologists… One gynecologist told me to my face that I was lying," the actress admitted. "That I must be eating terribly, and I must be doing everything wrong because ‘look at you,’ was essentially what he said."
"I just wanted somebody to test my blood… It was the most frustrating experience…and disheartening because no matter what I did, no matter how well I behaved, no matter how great I treated my body, things were actually getting worse rather than better. It was very, very confusing," she explained.
Sasha Pieterse is pictured at an event in 2013, left, and on the Warner Bros. lot in 2017. (Paul Archuleta/Jerritt Clark/Getty Images)
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Pieterse said she was eventually referred to an endocrinologist, who was able to diagnosis her with polycystic ovary syndrome (PCOS) practically right away.
PCOS is defined by the Mayo Clinic as being a "problem with hormones that happens during the reproductive years. If you have PCOS, you may not have periods very often. Or you may have periods that last many days. You may also have too much of a hormone called androgen in your body."
Another common side effect is weight gain.
Sasha Pieterse's character of Alison DiLaurentis looked different throughout the series and on spin-offs. (Allyson Riggs/Jaimie Trueblood/Getty Images)
Pieterse said it was difficult growing up on television while experiencing such profound changes to her body.
"I had such a good experience, but at the same time it was very intense for those 7 years… It's really intense to learn and grow and understand yourself when everyone else is hyper-analyzing it," she shared.
Sasha Pieterse revealed her PCOS is now dormant. (Paul Archuleta/Getty Images)
Pieterse, 27, says that having her son Hendrix actually regulated her hormones, so much so that her PCOS is now dormant. She explained that childbirth can, albeit rarely, help women with the problem.
Caroline Thayer is an entertainment writer for Fox News Digital. Follow Caroline Thayer on Twitter at @carolinejthayer. Story tips can be sent to
