Pregnant women should not be scared of using sunscreen to protect themselves from skin cancer despite safety concerns raised in animal studies, Canadian doctors say.

The July issue of Consumer Reports includes sunscreen ratings based on protection from UVA and UVB rays that cause damage such as sunburn, and tests of water resistance claims. The article also raises questions about potential harmful health effects on a fetus from a compound found in some sunscreens called retinyl palmitate. 

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Canadians are advised to choose a sunscreen that is water resistant with an SPF of at least 30. (John Russell/Associated Press)

"Retinyl palmitate [look for it among inactive ingredients], a type of topical vitamin A, is an antioxidant that animal studies have linked to an increased risk of skin cancers. In skin, it converts readily to retinoids, associated with a risk of birth defects in people using acne medications containing them. As a precaution, pregnant women may want to avoid sunscreens with retinyl palmitate," the magazine said.

"More research is needed, but as of now, the proven benefits of sunscreen outweigh any potential risks."

But warning pregnant women against using sunscreen with retinyl palmitate based on the findings of animal studies that use much higher doses than can be absorbed through the skin is unwarranted, said Dr. Gideon Koren, director of the Motherisk program at Toronto's Hospital for Sick Children.

"Scaring pregnant women is a national sport both here and in the United States," Koren said in an interview Wednesday. "The rat studies [have] never shown sunscreen to cause malformations."

Koren published a study in the medical journal The Lancet that showed babies born to mothers taking a topical cousin of vitamin A, isotretinoin, found in an acne medication, were fine.

"You need to poison yourself with vitamin A almost," Koren said, adding the "misinformation" scares women against using sunscreen and increasing their risk of melanoma.

Melanoma is a less common and most dangerous type of skin cancer. The Canadian Cancer Society estimates that 5,500 new cases of melanoma will be diagnosed in the country this year.

"There have been no studies in humans to show that there have been any problems," said Dr. Cheryl Rosen, a dermatologist at Toronto Western Hospital and director of the Canadian Dermatology Association's sun awareness program.

"I really do think we need to look at sunscreens in a positive note because the benefits outweigh the risks that are mostly theoretical. We don't have actual risk."

The cancer society recommends that people: 

  • choose a sunscreen that is water resistant with an SPF of at least 30.
  • reapply your sunscreen every two hours and after swimming or sweating.
  • make sure the product offers both UVA and UVB protection, usually labelled "broad-spectrum."  

Dermatologists also recommend applying about a shot glass full of sunscreen about 30 minutes before going outside.

Last summer during her pregnancy, Rhonna Rodriguez of Winnipeg said she avoided sunscreens and tried to stay out of the sun.

"It's very confusing," Rodriguez said of the advice offered by other mothers on what to do and not do. She now has seven-month-old twins.

Health Canada said it is aware of emerging concerns on retinyl palmitate, noting "there is no conclusive evidence confirming an association between retinyl palmitate and an increased incidence of skin cancer in humans."

"Canadians can be assured that manufacturers are required to have pre-market authorization from Health Canada for sunscreen products demonstrating that they are safe and effective prior to sale," the department said in an email.

With files from CBC's Melanie Glanz and Heather Evans