“Spending some time outside is perfectly safe during pregnancy,” says Kristin A. Dolling, MD, an obstetrician-gynecologist (OB-GYN) at Northwestern Medicine. “The biggest concerns aren’t the sun itself, but rather overheating and becoming dehydrated.”

As your body works harder to support your growing baby, it’s also less tolerant of heat. Here’s what you need to know before heading outdoors.

Why Heat Matters More Than Sunshine

Many people assume ultraviolet (UV) rays are the greatest concern during pregnancy. While protecting your skin from UV damage is important, Dr. Dolling says overheating and dehydration pose the greater risk.

During pregnancy, your body undergoes several changes that affect how it handles heat. Blood volume increases, more blood flows to the skin and your body begins sweating at a lower temperature to help cool itself. Despite these adaptations, prolonged heat exposure can still overwhelm your body’s cooling system.

“Pregnancy places additional demands on the body,” says Dr. Dolling. “If you’re spending too much time in hot or humid conditions, it’s easier to become dehydrated or overheat.”

Research has linked prolonged exposure to extreme heat during pregnancy with an increased risk of complications, including preterm birth, stillbirth, hypertensive disorders of pregnancy and certain birth defects. The risk increases as temperatures rise and with longer periods of heat exposure.

How Much Sun Is Safe?

For most people who are pregnant, brief periods of sun exposure are beneficial.

About 15 to 30 minutes of sunlight a few times each week can help your body produce vitamin D, which supports bone health for both you and your baby.

Dr. Dolling notes that recommendations don’t change based on which trimester you’re in. Instead, pay attention to the weather.

“If it’s especially hot or humid, you’ll need to be more cautious regardless of how far along you are,” she says.

To reduce your risk of overheating, plan outdoor activities before 10 am or after 4 pm, when the sun’s rays are less intense.

You can also get vitamin D from foods, such as fatty fish, fortified milk and prenatal vitamins to avoid unprotected sun exposure.

Pregnancy Can Make Your Skin More Sensitive

If you’ve noticed your skin reacts differently during pregnancy, you’re not imagining it.

Higher levels of estrogen and progesterone can make skin more sensitive to sunlight, increasing your likelihood of burning or developing dark patches.

One of the most common skin changes is melasma, often called the “pregnancy mask.” It causes patches of darker skin, usually across the cheeks, forehead, nose and upper lip.

“Melasma affects up to 75% of pregnant women and sun exposure can make it worse,” says Dr. Dolling.

Daily sun protection can help prevent existing discoloration from becoming more noticeable.

How To Safely Be Outdoors During Pregnancy

A few simple precautions can help you enjoy time outside while protecting both yourself and your baby.

• Drink water before, during and after being outdoors.
• Wear lightweight, loose-fitting clothing.
• Seek shade whenever possible.
• Avoid spending long periods outside during extreme heat or high humidity.
• Take breaks in an air-conditioned building or vehicle if you begin to feel overheated.
• Avoid strenuous physical activities during the hottest part of the day.
• Monitor local weather alerts during heat waves and adjust your plans as needed.
• Wear a wide-brimmed hat and UV-protective sunglasses.
• Apply a broad-spectrum sunscreen with a sun protection factor (SPF) of 30 or higher and reapply every two hours after swimming or sweating.

Dr. Dolling recommends choosing a mineral sunscreen containing zinc oxide during pregnancy instead of chemical sunscreen filters whenever possible.

The American Academy of Dermatology also recommends mineral sunscreens containing zinc oxide or titanium dioxide because they’re gentle on sensitive skin and provide broad-spectrum protection.

When To Get in the Shade or Go Indoors

Listen to your body if you’re spending time outdoors. Warning signs that you’ve been in the heat too long include:

• Feeling unusually thirsty
• Dizziness or lightheadedness
• Headache
• Fatigue or weakness
• Dark-colored urine or decreased urination
• Painful sunburn

“If you develop significant dehydration or a severe sunburn, contact your doctor,” says Dr. Dolling. “Some patients may require medical evaluation or intravenous fluids.”

Who Should Be Extra Careful?

Some people who are pregnant need to be especially mindful of heat exposure.

According to Dr. Dolling, those with high blood pressure or preeclampsia may be more susceptible to reduced blood flow between the placenta and baby during heat exposure. People with anemia may also have a harder time regulating body temperature because their blood carries less oxygen.

If you have one of these conditions, talk with your OB-GYN about the safest way to spend time outdoors during warm weather.

What To Remember About Sun Safety During Pregnancy

You don’t have to avoid the sun while you’re pregnant. The key is balancing outdoor time with smart sun safety habits.

“Stay hydrated, avoid prolonged heat, wear sunscreen and pay attention to how your body feels,” says Dr. Dolling. “With a little planning, you can safely enjoy being outside throughout your pregnancy.”