NEW YORK (CBSNewYork) -- They're cold, they're tired, or they're possibly gaining weight unexpectedly.
It's a hidden illness affecting many women, and they can wait years before they get a correct diagnosis.
AS CBS2's Dr. Max Gomez reports, Vicki Wayne and Anne Downes share something in common.
"Feeling tired all the time is not normal," Wayne said. "Feeling cold all the time is not normal."
Downes describes it as "a constant state of insomnia and exhaustion."
"I felt like something was wrong," she added. Eventually, both finally got the right diagnosis of an under-active thyroid, or hypothyroidism, which they believe may have went undiagnosed for decades.
"In that time I got married, I had my kids," Wayne said. "So you think, 'I'm tired because I've got two toddlers at home or my life is too stressful'."
"It could have prevented a lot of things wrong like infertility and weight gain," Downes said.
Endocrinologist Dr. Sarah Nadeem says many others may be suffering in silence.
"If you were to look at a group of women, one in eight will actually have some sort of thyroid disease," she tells CBS2.
According to the American Thyroid Association, women are five to eight times more likely than men to have trouble with their thyroid, and 60 percent go undetected.
"The majority of thyroid disease is actually auto-immune, so basically that means your own body makes cells that will attack the thyroid gland," Dr. Nadeem said.
Symptoms of hypothyroidism can mimic menopause, and may include fatigue, weight gain, dry skin, and hair loss.
While it's not clear why hypothyroidism is rising, doctors say the treatment is usually straightforward -- thyroid hormone replacement like Synthroid.
"Once you start getting the medicine and you start feeling better it's like 'wow, I have a little bit more energy. Oh, I have even more energy,'. So it's almost like night and day," Wayne said.
"I wake up more rested," Downes said. "It feels like I'm more normal. Like a more normal human being."
A simple blood test for hormone levels will tell if your thyroid is underactive. Boosting those levels is a matter of taking a tiny pill in the morning.
Some experts say Synthroid is over-prescribed and that if your symptoms don't get better after a year or so on the medication, they may not be due to your thyroid.
for more features.