Dear Doctor: Will taking acetaminophen (Tylenol) during pregnancy increase the chances that the child will have ADHD or autism?

Dear Reader: Such concern is understandable. Parents and parents-to-be have been alarmed over the past few years by two Danish studies that raise the specter of greater ADHD and autism risks among children whose mothers took the over-the-counter pain killer acetaminophen during pregnancy. But let's look at these studies a little more closely.

The largest of these studies showed that, among children whose mothers ever used acetaminophen during pregnancy, 5.7 percent showed symptoms of hyperactivity by age 7. Among children whose mothers never took acetaminophen, 4.3 percent showed symptoms of hyperactivity. Similar mild differences were also noted for emotional problems and overall conduct.

Here's the important caveat: The two groups of women were themselves very different. Participants who used acetaminophen were more likely to be smokers, more likely to be obese (BMI greater than 30) and more likely to have had a fever. Just having a fever during pregnancy has been associated with autism, behavioral abnormalities and problems with attention.

As for the autism study, it linked acetaminophen use during pregnancy to an IQ drop of 2 points in 5–year-olds. Here, the cause of the acetaminophen use is an especially important factor. In this study, 37 percent of the mothers who used acetaminophen had fever; only 23 percent of those who didn't use acetaminophen had fever. And again, those who used acetaminophen were more likely to be smokers.

So one has to ask: Why does someone take acetaminophen during pregnancy? The answer: To reduce a fever. So fever may be the problem, not the acetaminophen. Further, women who smoke and are obese are more likely to be unhealthy during pregnancy, more likely to take acetaminophen for physical problems and more likely to have children who may also be less healthy.

Would I recommend acetaminophen regularly in pregnancy for joint pain and muscle aches? Probably not, though I would take it for a fever and for moderate pain. Otherwise, it's better to do prenatal yoga, gentle stretching and maintain a good diet.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

Dear Readers: Welcome to the second day of our new "Ask the Doctors" column. As an internist and primary care physician at UCLA Health, my approach to medicine is to understand that I don't have all the answers -- that I have to learn new topics and review old topics all the time.

Sometimes, I can provide answers right away. But sometimes, I have to stop and reassess. Medicine has seen many breakthroughs since I graduated from medical school nearly 20 years ago, and evidence has changed many dogmatic ways of practice.

Objective, non-biased data are important to the practice of medicine. Doctors must understand how that data can be applied to one person or to large groups of people.

You met my colleagues Dr. Eve Glazier and Dr. Elizabeth Ko yesterday and learned about their approach to health and wellness. My column focuses on commonsense answers based upon scientific literature. As I increase my professional knowledge, I hope to provide people with thoughtful and deliberate interpretations of medical science that people can use to direct their own health.

Dear Doctor: My job requires me to sit in front of a computer for at least eight hours a day. When I come home, I usually watch television for a few hours before going to bed. Is being so sedentary bad for me?

Dear Reader: Unequivocally, yes. Many studies of many types have found increased death rates among people who sit for prolonged periods. The biggest problem is being sedentary in front of a television.

The average American watches more than four hours of television per day. Some studies have found that for every additional two hours in front of the television, the risk of diabetes increases 14 to 20 percent.

Here's why: Sitting for prolonged periods decreases insulin sensitivity, meaning your blood sugar rises. Add to that the types of sugary foods that are often eaten while watching television, and you have the creation of a serious health problem. If you're sedentary throughout the day, exercise can help ease the negative impact, but not completely make up for it.

So for starters, watch less television or, if you do watch television, put an exercise bike in front of the screen. Second, if you have a job in which you sit for long periods, take three-minute breaks every 30 minutes to stretch and walk around a little. Every little bit of activity helps.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

Dear Readers: Welcome to the launch of a new column -- "Ask the Doctors." Together with a colleague, we take over for "Ask Doctor K," in which Dr. Anthony Komaroff dispensed timely advice and guidance to readers. We plan to continue in this same tradition by offering answers to your questions about health and wellness.

"We" are Dr. Eve Glazier and Dr. Elizabeth Ko, internists and primary care physicians at UCLA Health. Our specialty is internal medicine, with a focus on the management and prevention of chronic disease. We share this column on alternating days with our colleague, Dr. Robert Ashley, whose introduction will be published tomorrow.

What brings us to this column is a lifelong passion for both learning and teaching. We take a lively interest in all areas of health and wellness.

Amid a flood of information -- and misinformation -- available these days, our goal is to provide not just facts and statistics but also context and nuance. We want to give you the tools you need for a healthy and happy life.

We are firm believers that knowledge can help you to take control of your health and well-being.

Dear Doctor: We have always been careful to put our son to sleep on his back to prevent SIDS, but he has recently started turning over by himself, and we find him on his stomach. Should we prevent this? Should we put him on his back again?

Dear Reader: You're right that placing infants on their backs to sleep greatly reduces the rate of Sudden Infant Death Syndrome (SIDS), the leading cause of death in infants between 1 month and 1 year old. About 1,500 infants die of SIDS each year in the United States, with most of the cases occurring in babies younger than 6 months old.

The good news is that once your baby is able to turn over by himself, which happens at about 6 months, his brain is developed enough to alert him to breathing problems. Rolling over is an important part of his development, and he should be allowed to do so.

You should continue to place him on his back when you put him down to sleep, but according to guidelines published by the National Institutes of Health, you don't need to return him to his back when he turns over. At that point, it's OK to let your baby choose his sleep position.

You should also:

-- Be sure to use a firm mattress with a fitted sheet.

-- Keep his crib clear of soft objects like pillows, stuffed toys, crib bumpers or loose bedding.

-- Overheating may play a role in SIDS, so keep his room at a comfortable temperature and don't overdress him for bed. He may be too warm if his chest feels hot or if he is sweating.

-- Don't cover him with loose bedding such as a blanket, quilt or sheet, as he may get tangled up.

-- Do keep your baby close by in your room, but don't sleep with him in your bed. The risk of accidentally rolling over on the baby or of him falling out of the bed is too great.

Follow these simple precautions to give your baby the safest sleep environment. And congratulations on your son's milestone of turning over by himself!

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)