When the mole on Kristin Nyerges’ neck began to change during pregnancy, the mom-to-be didn’t think much of it. After all, she’d had the mark since birth and knew skin changes aren’t uncommon during pregnancy. But when Nyerges’ colleague at the Willoughby, Ohio, hospital where she works advised her to get it checked out, she was glad she did.

The 31-year-old was diagnosed with melanoma, the deadliest form of skin cancer, but her doctor caught it early— a reality that posed a risk of transmission to her unborn baby, but a stage that ultimately meant good survival odds for her and her child. After undergoing surgery to remove the mole, Nyerges is cancer free, and her baby is due later this month.

“Now, I wear SPF when I’m going outside— even if it’s just for a walk,” Nyerges, an assistant nurse manager in critical care at West Medical Center, told FoxNews.com. “I’m just so happy that we were able to catch it early.”

If you talk to any woman who’s been pregnant, she’ll likely tell you she noticed her skin changed while carrying her child. But scientists speculate the hormonal and immune system variations that accompany transitional phases like pregnancy may increase the risk of skin cancer.

Nyerges’ doctor Brian Gastman, director of melanoma in the melanoma program at the Cleveland Clinic, concluded in a study published earlier this year that, compared with pregnant women not diagnosed with melanoma, women who were diagnosed with the disease within one year of giving birth were five times as likely to die from melanoma, seven times as likely to see their cancer spread, and nine times as likely to see the disease recur. The study was published in January in the Journal of the American Academy of Dermatology.

Research suggests pregnancy suppresses the immune system, which can increase an individual’s risk of illness, including cancer, but hormonal changes during pregnancy may also lead to greater mutation of cancer cells, expediting their proliferation, Pedram Gerami, director of the melanoma program at the Northwestern University Skin Cancer Institute, told FoxNews.com. Gerami was not involved in the Cleveland Clinic study, nor has he treated Nyerges.

“As a melanoma matures and goes through increasing stages, it can acquire a number of different mutations, and some of those mutations that it can acquire are mutations that would divide, and increase in number or increase in action, when it is exposed to certain hormones,” Gerami said. Studies and underlying mechanisms of some types of immunotherapy suggest those hormones include estrogen and progesterone, which are elevated during pregnancy.

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Gerami conducted a study published in the November 2015 edition of the Journal of the American Academy of Dermatology that suggested similar results to Gastman’s study. But while Gastman’s research subjects had variable stages of skin cancer diagnoses during observation— with patients whose skin cancer was stages 2, 3 and 4 seeing the highest risks— Gerami’s study focused on patients diagnosed earlier. His findings didn’t draw a link to an increased risk of skin cancer diagnosis, metastasis and recurrence.

Both studies had small sample sizes— the Cleveland Clinic’s had about 400, and Northwestern’s had about 170, and both were observational.

“I think we need to keep in mind both the study we did and [the Cleveland Clinic] study are retrospective, case-controlled studies, and really what would be the most convincing level of a study would be a prospective cohort study,” Gerami said. “But nonetheless, for the data we have at this time, these are very important findings and certainly would suggest that patients who have a melanoma during pregnancy or around the period of a year from pregnancy— especially those that are at least a stage 2 or higher— need to have very careful and close follow-up.”

In pregnant women whose melanoma ends up spreading to her child, women have the option to coordinate with their doctor to determine the next best steps.

“There have been reports of melanoma spreading, and I know cases where both the mother shortly died after birth and the baby died of melanoma in the first year,” Gastman, also a plastic surgeon and an associate professor of surgery at the Cleveland Clinic Lerner College of Medicine, told FoxNews.com. “The bigger issue tends to be not whether it spreads from the mother, but, if you’re going to cure the mother, you have to do something to the mother that would hurt the baby.”

Gastman has seen women diagnosed with the disease decide to have their doctors induce labor, and he has seen women forgo treatment and continue with high-risk pregnancies under the supervision of their OB-GYNs. He also has seen some women decide to terminate their pregnancies because the most likely consequence for both mother and child was death.

“Those are personal, ethical questions that the patient and their OB-GYN have to make,” he said.

Nyerges’ cancer was diagnosed at the early stage of T1A, but Gastman estimated that, without treatment, the risk her melanoma could have been spread to her baby was 20 percent.

“It was relatively early but not nearly enough for us to not worry about metastasis,” he said. “She did not have [metastasis], but to figure that out, we had to do surgery. A CAT scan is not perceptive enough.”

For surgery, she opted for localized anesthesia, which is thought to be safer for pregnant women than general anesthesia, as it could harm developing children, Gastman said.

The average 20-year survival rate of stage T1A melanoma is 93 percent, but because Nyerges was pregnant, her prognosis may be different.

“We don’t have good data to say what the 20-year survival rate will be in that group or if that number may be lower. That’s why further research … is so critical,” said Gastman, who added that, based on his analysis, Nyerges’ prognosis is good.

Figuring out a woman’s true risk of melanoma recurrence after diagnosis during pregnancy would be crucial for women who want to have additional children, Gerami noted. But he cautioned against alarm among women like Nyerges who have early-stage melanoma, and estimated those women’s risk of recurrence would be the same regardless of whether they are pregnant.

Scientists estimate that, in 2016, there will be about 74,000 new melanoma diagnoses in women, and that one-third of those will occur during childbearing age— and 40 to 50 percent of that fraction will all be stage 1 or earlier.

As scientists work to better understand the relationship between pregnancy and skin cancer, Gerami said the only modifiable risk factor for the disease that scientists know for sure is sun exposure.

“Of course we know genetics is a big part, but the only part we can modify is sun protection,” he said, adding that wearing sunscreen during the winter is as important as it is during the summer.

Knowing the signs of melanoma can help as well. Gastman detailed the “ABCDE” rules for possible melanoma: a mole that “A,” has asymmetrical shape; “B,” has a border that’s uneven; “C,” has a dark or homogenous color; “D,” has a diameter of over 6 millimeters; and “E,” is elevated or has evolved.

Those individuals with light physical features like blond hair and blue eyes, as well as those with more than 50 moles on the skin, are thought to be at a greater risk for the disease.

Nyerges, who has light features, is due June 23, and she and her husband, Jason, are expecting a baby boy.

She described her former self as a “sun lover” who would sit outdoors for hours on end without reapplying sunscreen.

“I have not sat out in the sun just to sunbathe since this whole incident,” she said. “When my baby is here— and we’ll take him to the pool eventually, when he’s able to— I’ll make sure I have a hat on and make sure I sit in the shade now versus trying to get as much sun.”