Debunking myths about pregnancy hazards

What about heat? Is it true that pregnant women should stay out of hot tubs, saunas and Jacuzzis?

True. These wonderfully relaxing activities can raise mom’s temperature to over 101 degrees Fahrenheit. The fetus has a temperature that is approximately 1 degree Celsius above that of the mom, and when mom’s temperature goes up too high, so does that of the fetus, to an even greater extent. Animal studies show that when the mother’s core temperature goes up, there is an increase in miscarriage and birth defects. So avoid hot tubs, Jacuzzis and saunas in early pregnancy. Also, exercise can cause a pregnant woman to become overheated (over 101 degrees Fahrenheit). So pregnant woman are advised not to exercise outside for long periods if it’s hot or humid. And when exercising, it’s important to drink plenty of fluids; dehydration raises body temperature. (A good rule to follow: Drink one glass of water every 20 minutes during a workout.)

And remember, (especially now that it’s summer), prolonged sunbathing can raise body temperature. It’s therefore important that pregnant women stay in the shade and keep cool when outdoors.

What about getting an X-ray?  Shouldn’t X-rays be avoided by pregnant women?

True. But according to the American College of Radiology, no single diagnostic X-ray results in radiation exposure to a degree that threatens a developing embryo or fetus; so if a single test is needed for health, it’s okay. But multiple X-rays or any X-rays that are less than essential should be postponed until after delivery.

What about video display terminals?  Is it all right for a pregnant woman to sit in front of a computer, especially for prolonged periods of time?

Yes. So far there is no scientific evidence that a pregnant woman needs to limit her time in front of a computer screen. Video display terminals (VDTs) don’t emit any form of dangerous radiation from the front, but do emit low-frequency electromagnetic radiation from the back of the device. The effect of the latter on pregnancy is not known. However, because ligaments are loosened and there is more fluid retention in pregnancy, prolonged use of the keyboard and incorrect positioning are more likely to cause carpal tunnel syndrome in pregnant women.

Hair dyes?  You shouldn’t dye or perm your hair in pregnancy?

False. There is no direct evidence that either will cause mutations, but I present this permission “to keep roots and highlights in good condition” with the caveat that there is very little medical data on this hair color or styling issue. One study did show that cosmetologists had a higher rate of miscarriage, so if a pregnant woman is a hairdresser and chronically exposed to chemicals, she should wear gloves and perhaps reduce this part of her job during the first trimester.

Painting —  don’t use lead paint while pregnant.

True. Inorganic pigments may contain not just lead but also chromium, cadmium, cobalt, nickel and mercury. Lead is of chief concern because it easily crosses the placenta, and a high level in pregnant women is associated with an increased risk of miscarriage, decreased infant IQ and stillbirth. So if you paint pictures or walls, check labels and avoid paints that contain lead.

Air travel.  Don’t fly in your first trimester.  Radiation from high-altitude flying can hurt your baby.

False. Air travel will not cause miscarriage. The only concern is that if you are going to miscarry because your pregnancy is abnormal, you don’t want to start bleeding at 30,000 feet or far from your physician’s care. (I generally check a patient in early pregnancy with ultrasound to ensure viability before she travels out of town.)  Nor do you want to go into labor while traveling. So most women should stop flying after 36 weeks’ gestation.

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The environment in passenger cabins is the equivalent of 5000 to 8000 feet of elevation and, unless a pregnant woman has cardiac or lung problems, this altitude, especially for a brief flight, should be okay. Because the humidity in a plane is low, it’s important to hydrate, and because pregnancy itself can increase risk of deep vein thrombosis, it’s especially important to get up, walk around and change position in flight. 

There is more radiation at high altitudes, but the amount in a single round-trip cross-country flight is well below safe upper limits. Radiation, however, is cumulative, and pregnant women who are frequent fliers or work in flight airplanes should keep track of their exposure. This can be done by going onto the FAA radiation estimation software. 

Pregnancy is an amazing time when a woman’s body goes through many changes. Although there are some definite “no-no’s,” many of our normal activities can be continued, especially if we follow the dictum “with moderation.”

Dr. Judith Reichman, the TODAY show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," which is now available in paperback. It is published by William Morrow, a division of HarperCollins.

PLEASE NOTE: The information in this column should not be construed as providing specific medical advice, but rather to offer readers information to better understand their lives and health. It is not intended to provide an alternative to professional treatment or to replace the services of a physician.

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