Mercury and pregnancy
Mercury is a metal. If you come in contact with high levels of mercury during pregnancy, it can cause real problems for you and your baby.
Mercury can damage many parts of your body, including your lungs, kidneys and nervous system (that includes the brain, spinal cord and nerves). It also can cause hearing and vision problems. How serious the damage is depends on how much mercury you’re exposed to. Babies exposed to mercury in the womb can have brain damage and hearing and vision problems.
How can you be exposed to mercury?
Mercury has several forms:
- It can be a colorless, odorless, poisonous vapor in the air. It’s released into the air when it’s spilled or when something that contains it breaks. It’s also released through industrial processes, like burning waste or burning coal in power plants.
- It can fall from the air back to earth and build up in oceans, lakes, rivers and streams. Fish get mercury from the water they swim in and from eating other fish that have mercury in them.
- It’s a shiny, silver-colored substance used to make dental fillings, fever thermometers and other products.
You can be exposed to mercury through:
- Your skin, by touching it
- The air, by breathing it in
- Eating or drinking food or water contaminated with it
How can you keep yourself safe from mercury?
Here’s what you can do:
- Don’t eat fish that contain high amounts of mercury. These include shark, swordfish, king mackerel and tilefish.
- If you need to get a filling, ask your dentist about filling options. You may be able to have a filling that doesn’t contain mercury. Don’t have any mercury fillings removed unless they’re broken or damaged. Be sure your dentist knows you’re pregnant before you have any dental work done.
- Don’t use a vacuum cleaner to clean spilled mercury.
- Ask an adult who’s not pregnant to throw away any broken thermometers or fluorescent light bulbs. Store these items in a way that prevents them from breaking, and don’t let children use them.
- If you may be exposed to mercury at your job (like in a dentist’s office or do electrical, chemical or mining work), talk to your boss about safety precautions. For example, you may work in a dentist’s office, do electrical, chemical or mining work, or use mercury to make products. Ask if you can switch to a different position or task during pregnancy.
Talk to your health care provider about protecting yourself from mercury.
What is methylmercury?
Methylmercury is made when mercury in the air gets into water. The mercury in the air comes from natural sources (such as volcanoes) and man-made sources (such as burning coal and other pollution).
You can get methylmercury in your body by eating fish that contain a lot of mercury. These fish get mercury from the water they swim in and from eating other fish that have mercury in them. Mercury is mostly found in large fish, like swordfish, shark, king mackerel and tilefish. During pregnancy, don’t eat these kinds of fish because the mercury in them can harm your baby.
During pregnancy, eat 8 to 12 ounces each week of fish that are low in mercury, like shrimp, salmon, pollock, catfish and canned light tuna. It’s OK to eat 6 ounces a week of albacore (white) tuna.
What is elemental mercury?
Elemental mercury (also called pure mercury) is a shiny, silver-colored substance. When it’s spilled or something that contains it breaks, the mercury becomes an invisible, odorless and poisonous in the air. Elemental mercury may be found in:
- Dental fillings made from amalgam. Amalgam contains elemental mercury, silver and other metals. Small amounts of mercury from these fillings can get into the air you breathe. Amalgam fillings are safe for adults and children over age 6. But we don’t know their effects on pregnant women. If you’re worried about having an amalgam filling, talk to your dentist or health care provider.
- Fever thermometers. Mercury in fever thermometers is surrounded by glass. It’s not harmful unless the glass breaks and you touch the mercury or it gets into the air you breathe. If you break a thermometer, don’t vacuum the spilled mercury. Instead, use a piece of paper to roll the beads of mercury onto another piece of paper. Seal the paper in a plastic bag. Contact your local health department to ask how to throw the mercury away.
- Some antiques, like clocks, barometers and mirrors.
- Some button cell batteries, like watch batteries. Most batteries made in the United States don’t contain mercury.
- Some jewelry, especially glass pendants made outside the United States
- Skin-lightening creams made outside the United States
If you’re worried about being exposed to elemental mercury, talk to your health care provider.
Last reviewed June 2014
See also: Environmental risks and pregnancy
Frequently Asked Questions
Is air travel safe during pregnancy?
If your pregnancy is healthy, it’s usually safe to travel by plane. Follow these tips when traveling by air:
- Ask your airline if they have a cut-off time for traveling during pregnancy. You can fly on most airlines up to 36 weeks of pregnancy. But if you’re flying out of the country, the cut-off time may be earlier.
- If you’ve had morning sickness during pregnancy, ask your provider if you can take medicine to help with nausea.
- Book an aisle seat so you don't have to climb over other passengers when you need to get up to use the restroom or walk around. Try sitting towards the front of the plane where the ride feels smoother.
- Drink plenty of water. Don’t drink carbonated drinks, such as soda. And don’t eat foods, such as beans, that may cause gas.Gas in your belly can expand at high altitudes and make you feel uncomfortable.
- Fasten your seat belt when you’re in your seat. This can help keep you from getting hurt in case of turbulence. Turbulence happens when the air around a flying plane causes a bumpy ride.
- Wear loose, comfortable clothing. Flex your ankles during the flight, and take a walk when it's safe to leave your seat. Doing these things can help your blood flow and lower your risk of deep vein thrombosis (DVT), a blood clot inside a vein. Sitting for long stretches of time during any kind of travel raises your chances of having DVT. Ask your health care provider if you should wear support stockings during your flight. They may help prevent DVT. But if you have diabetes or problems with blood circulation, you probably shouldn’t wear them.
- Tell the flight attendant if you feel sick or very uncomfortable during your flight. Contact your health care provider as soon as you can.
Is it safe to get or have a tattoo during pregnancy?
It's best to wait until after having your baby to get one. Here's why: Hepatitis B, a dangerous liver infection, and HIV/AIDS are two of many diseases that can be passed along through bodily fluids. This means you can catch these diseases if you get a tattoo from someone who uses a dirty needle. And you can pass these diseases along to your baby during pregnancy.
We don't know how tattoo dyes and inks affect a developing baby. Small amounts of chemicals that might be harmless to an adult can have a much bigger impact on a growing baby.
Most healthcare providers will give an epidural to a woman with a tattoo on her lower back. But they may decide not to if the tattoo is recent and fresh. If you have a tattoo on your back and are considering getting an epidural for pain relief during childbirth, find out what the hospital's policy is before you're admitted.
Is it safe to get spa treatments during pregnancy?
Some spa treatments are safe. Others may be more painful than usual. And some - like mud baths - are a bad idea while you're pregnant.
Any spa treatments that raise your body temperature (like mud baths, hot wax and seaweed wraps) are almost always unsafe during pregnancy. Steam rooms, hot tubs, and saunas also raise your body temperature. They can make you dehydrated and overheated. This can be dangerous for you and your baby. Avoid these treatments while you're pregnant.
Be careful with skin treatments like facials and body scrubs. During pregnancy, your skin changes a lot and may be extra sensitive. Before you cover your whole body with a product, test it on a small area of skin to be sure it doesn't irritate.
Getting your eyebrows done and having your bikini line waxed are usually safe during pregnancy, but they may feel more painful to your sensitive skin.