Pregnant women love their flawless complexion and radiant “pregnancy glow,” despite having to deal with other not-so-flattering skin changes like stretch marks, skin tags and varicose veins.

Yet there’s a skin condition that, while common during pregnancy, can take women by surprise— melisma.

Here, find out what melasma is, why it happens, if you’re at risk and what you can do about it.

What is melasma?
During pregnancy, melasma is referred to as chloasma gravidarum and colloquially, “the mask of pregnancy.”

The skin condition causes brown or gray-brown patches to appear on the face usually in a symmetrical pattern. Although melasma can show up anywhere, it’s common on the cheeks, upper lip, forehead and chin.

“It’s significantly less common to have pigmentation in other areas of the body, ” said Dr. Bethanee Schlosser, a board certified dermatologist and assistant professor in the department of dermatology at Northwestern University Feinberg School of Medicine in Chicago, IL.

Melasma occurs when a group of skin cells that produce melanin, known as melanocytes, are activated and stay that way. As the melanocytes continue to produce more pigment, the skin gets darker, said Dr. Zein Obagi, a dermatologist in Beverly Hills, Calif.

Melasma occurs in all skin types and colors, but it’s most common in women with light to medium skin tones. So women who are of Latino, North African, African-American, Asian, Indian, Middle Eastern and Mediterranean descent are more likely to develop it.

Although melasma usually shows up between the first and second trimesters, it can happen at any point in pregnancy, Schlosser said.

Risk factors
According to the National Institutes of Health, 50 to 70 percent of pregnant women will have melasma. Melasma is also more likely to reoccur with subsequent pregnancies.

Women who are affected often have a genetic predisposition.  In fact, a recent study in the journal Dermatology and Therapy found that 31 percent of women with melasma had a family history of the condition as well.

Studies show that exposure to ultraviolet light from the sun is also a significant contributing factor.

Hormones, specifically estrogen— which is high during pregnancy— and can also be elevated from birth control pills. Hormone replacement therapy can increase skin pigmentation, too.

It’s unlikely that melasma will clear up after delivery without treatment but if it does, it will happen in the first year postpartum.

“More recent studies have shown that melasma for the great majority of patients is chronic and can last for several years,” Schlosser said.

How to prevent and treat melasma
Like any other medical treatment during pregnancy, weighing the benefits and risks is important. Here are some things to consider.

See a dermatologist.
Your dermatologist will inquire about family history, look at the pattern of the pigmentation, and may use a Wood’s light. Similar to a black light, the Wood’s light can help your doctor determine if the hyperpigmentation is in the top layers of the skin or if it’s deeper and suggest appropriate treatment.

One thing you should know is that melasma’s only symptom is skin discoloration. So if you also have pain, tenderness or itchy skin, be sure to speak with your dermatologist immediately.  

Avoid the sun.
Protecting yourself from the sun is always a good idea, but it’s especially important if you have risk factors for melasma or are concerned that you may get it.  What’s more, if you’ve already had treatment for melasma, sun exposure will reverse any improvement, Schlosser said.

Look for sunscreens that say “broad-spectrum UVA/UVB,” those with an SPF of at least 50, and contain titanium dioxide or zinc oxide, which are deemed safe during pregnancy, Schlosser said.  Wear a wide-brimmed hat, sun-protective clothing, and try to stay in the shade as much as possible.

“If you have sun exposure, you’re going to reverse that improvement,” she said.

Consider treatment.
Most treatments for melasma are not safe during pregnancy or while breastfeeding. Some like azelaic acid, a topical cream and a glycolic acid chemical peel, are considered safe but you should weigh the risks and benefits with your physician. What’s more, many treatments like hydroquinone fall short because they only treat the skin’s surface, not the melanocytes on the cellular level, Obagi said. So talk to your dermatologist about the best treatment for you.  

Julie Revelant is a health journalist and a consultant who provides content marketing and copywriting services for the healthcare industry. She's also a mom of two. Learn more about Julie at revelantwriting.com.