Melanoma may be deadlier in pregnant women, study finds

Waiting for a baby. Close-up of young pregnant woman touching her abdomen while sitting on the couch (iStock)

Pregnant women with the skin cancer melanoma may be more likely to die from it than women with melanoma who are not pregnant, according to a new study.

Researchers found that women in the study who were diagnosed with melanoma during pregnancy or within one year of giving birth were more than five times more likely to die from the skin cancer than women with melanoma who were not pregnant.

Moreover, the women with melanoma who were pregnant at the time or were recently pregnant were nearly seven times more likely to experience metastasis the spreading of the cancer to other parts of the body than women with melanoma who were not pregnant. They were also more than nine times more likely to have a recurrence of their cancer over the next 7.5 years.

"When we looked at our data, we were shocked" to see the significantly higher rates of death, metastasis and recurrence of the cancer among pregnant women, said study author Dr. Brian Gastman, a plastic surgeon at Cleveland Clinic. [10 Dos and Donts to Reduce Your Risk of Cancer]

In the new study, the researchers looked at 462 women with melanoma who were younger than 50. Among them, there were 41 women who had been diagnosed with melanoma while they were pregnant or within one year of the time they gave birth. In this group, 20 percent of the women died from melanoma, compared with about 10 percent of the women who were not pregnant around the time when they were diagnosed with melanoma.

Moreover, in 25 percent of the women diagnosed with melanoma during pregnancy or soon after giving birth, the cancer spread to other parts of the body, compared with 12.7 percent of the women who were not pregnant.

And 12.5 percent of the women diagnosed with melanoma during or after pregnancy experienced a recurrence of their melanoma during the next 7.5 years, compared with just 1.4 percent of the other women.

The researchers "are not saying necessarily that [pregnant women] are more likely to get melanoma" than other women, Gastman told Live Science. However, if pregnant women do get melanoma, "that melanoma tends to be virulent, [and] more aggressive," than melanoma in other women, he said.

The researchers don't know for sure why melanoma appears to be more aggressive in pregnant women, but they said it might have something to do with hormonal changes that occur in pregnant women, such as increased levels of estrogen.

The greater aggressiveness of melanoma in pregnant women also could be related to the dampening of the immune system that occurs during pregnancy to prevent a woman's body from rejecting the fetus, the researchers said.

Previous research has shown that the rates of melanoma are on the rise among women ages 20 to 40, the researchers said.

The study serves as a reminder that any woman who has a higher risk of melanoma for example, because she has a high number of moles, a history of heavy exposure to the sun or a family history of skin cancer should be particularly vigilant about self-examining her skin for any changes, and should consider seeing a dermatologist, Gastman said. And if a woman already has a high risk of melanoma and she gets pregnant, "getting a dermatologist is key," he said.

The new study was published today (Jan. 20) in the Journal of the American Academy of Dermatology.