Taking Medication While Pregnant

Safe or Sorry?

Reviewed by Gary D. Vogin, MD

Feb. 11, 2002 -- When I was four months pregnant, I developed severe stomach pains and was rushed to the hospital. Suspecting appendicitis, the emergency room doctors advised X-rays -- the only way to find out if their suspicions were correct. I panicked. After all, X-rays were on that ominous list of "don'ts" I had so fastidiously been avoiding throughout my pregnancy.

The doctors agreed to monitor me carefully and to hold off for an hour or so. In the meantime, they grew less convinced that my discomfort was appendicitis and more sure I merely had a case of the flu and dehydration. But what I hadn't fully understood was that a burst appendix was far more dangerous to me and my baby than any X-ray.

My misguided fears aren't uncommon. Experts say many women -- and even some doctors -- think some medications and exposures are more harmful to a pregnancy than they actually are. It's a good idea to avoid substances you don't need, they say, but you shouldn't feel compelled to be a martyr, either.

"I think there are great misperceptions out there," says Karen Filkins, MD, director of reproductive genetics at the UCLA School of Medicine, who ran a pregnancy hotline in Pittsburgh for 12 years and fielded thousands of calls from pregnant women who were unduly worried about exposing their babies to everything from mouthwash to Ex-Lax.

Citing a variety of conditions from asthma to the common cold, Filkins says medications can often ensure safer pregnancies than if illnesses are left untreated. "In fact, the worst thing you can do is go cold turkey and stay sick. Fever, for instance, has more potentially damaging effects early in pregnancy than taking something like Tylenol."

Teratogens: The Tests of Time

Women have traditionally been cautioned against taking medications during pregnancy, because there are no guarantees that any drug is safe. The only way to do that would be to put the drugs through controlled trials with pregnant women, and no one wants to assume the ethical or legal liabilities of exposing a pregnant woman and their fetus to potential harm.

The U.S. Food and Drug Administration requires manufacturers to test drugs that might be used by reproductive-age women in pregnant animals, but the reactions in animals aren't always the same. Thalidomide, a sedative and antinausea drug used by pregnant women in Europe, produced limb deformities in nearly 6,000 babies born between 1956 and 1963, but did not affect pregnant rats. Fortunately, the drug was not approved in the United States.

Yet over the years, experts have accumulated data on the effects of an array of medications used by women during pregnancy. One of the largest such studies, published in the late 1970s, tracked 50,282 pregnant women who took a variety of drugs from 1958 to 1965. Drugmakers also must report any problems they find out about to the Food and Drug Administration, and doctors voluntarily do the same.

What scientists have found so far is that only a relatively small number of medications are known teratogens, substances that cause abnormalities in the growing fetus. About one out of every 33 babies is born with birth defects each year; about 2% to 3% of those are believed to be from drug exposure.

"There are very few medications you shouldn't take," says Jennifer Niebyl, MD, head of obstetrics and gynecology at University of Iowa College of Medicine, who has written chapters in medical textbooks on drugs during pregnancy. "Obviously you should check with your healthcare provider first, but if a mother needs medicine for medical illness, she should take it."

The FDA uses the data that's accumulated to classify drugs based on teratogenic risk. There are currently five categories: A, B, C, D and X. Type A drugs are the least harmful, and X have risks that clearly outweigh any benefits. The agency is considering a change to these categories to give doctors and the public a clearer picture of the data available.

In addition to the FDA lists, about 20 teratogen centers throughout the country are constantly updating a database of information on the effects of different drugs in pregnant women. "Having your doctor call and check with a hotline for the most recent information is a really rational thing to do," Filkins advises.

Experts also suggest that pregnant women stick to medicines that have weathered the test of time and avoid those for which there isn't as much data collected, such as some allergy medications recently introduced on the market. Commonly used antihistamines like chlorpheniramine, for instance, haven't been associated with a higher risk of birth defects.

"The Claritins, the Allegras -- the billion-dollar blockbuster drugs you see on TV -- we just don't know much about them. They may be safe during pregnancy; they may not," says Michael Zinaman, MD, a reproductive endocrinologist at Loyola Medical Center in Chicago who counsels patients on drugs to avoid during pregnancy.

Setting the Record Straight

In the 12 years that Filkins headed up the Pregnancy Safety Hotline in Pittsburgh, she was struck by the misinformation and needless fear reflected in many calls. One of the most common was from women who got pregnant while on birth control pills and worried that their babies would be born with VATER association, a series of limb and digestive defects.

"With the doses used today, it's not a very large concern, yet there are so many women who are frightened, and even terminated their pregnancies, because of older reports in the medical literature," Filkins says.

Another common confusion among pregnant women is exposure to X-rays. "There's still much hysteria out there, even though they can be lifesaving and the exposures from diagnostic X-rays rarely approach the 5 rad range at which we begin to have some concern," Filkins says. The risks really aren't suspect until 10 or 20 rads, she says.

Just as many medications may be safer than you think, some popular remedies also may be more dangerous to use during pregnancy than people think, says Filkins. For instance, popular megadose vitamins, which contain high doses of vitamin A, a fat-soluble vitamin, should be avoided, she says.

"There are people who feel that if a little bit of vitamins is good, more is better, but many women may not realize that very high doses of vitamin A found in the popular megadose vitamins could produce harmful effects," Filkins says. Pregnant women should avoid taking more than 5,000 international units (IU) of vitamin A daily, the amount contained in prenatal vitamins. Potential risks may occur at 25,000 IU or more.

Women should also consult their doctor or midwife before using herbs. Herbalists insist that pregnant women have been using herbal treatments with success around the world for years, and some herbs are standards among midwives, such as raspberry tea to prevent morning sickness and miscarriage and to strengthen the uterus.

But just because herbs are natural doesn't mean they're safe. Some trigger allergic reactions, others are toxic and some can be harmful in pregnancy, especially those that act as strong laxatives or promote uterine contractions. Among those to avoid: senna, cascara sagrada, buckthorn, mugwort, pennyroyal, juniper, rue, tansy, cottonroot bark, male fern, goldenseal, comfrey, sage in large amounts, coltsfoot, and black cohosh root.

In fact, a new study by researchers at Loma Linda University suggests that some popular herbs -- St. John's wort (used to treat depression), echinacea (used to strengthen the immune system and fight colds) and ginkgo (used to enhance memory) -- could block conception. But the researchers stressed that the test-tube study isn't proof that the same effects will occur in humans.


When deciding whether to take any medication during pregnancy, doctors and patients have to weigh the potential benefits against the risks. In many cases, the conditions may be serious enough to treat, including asthma, heart problems, high blood pressure and pneumonia, since the symptoms could pose a bigger threat to the mother and baby.

"It's in the fetus' best interest to have a healthy mother," says Roy Pitkin, MD, professor emeritus at UCLA Medical School and editor of the Journal of Obstetrics and Gynecology. "This attitude of conservatism gets carried too far when women don't take drugs that are clearly necessary for their own health, either because their doctors are afraid or because they're afraid to take them."

He says that corticosteroids, which are used to treat medical diseases such as asthma, are relatively safe to use during pregnancy. "Yet women get denied the treatment because of the misguided feeling that it may be harmful." Inhaled corticosteroids are also effective therapy, since very little drug is absorbed by the baby.

In other cases, the severity of the illness needs to be assessed. For example, the latest generation of antidepressant drugs, called selective serotonin reuptake inhibitors (like Prozac), don't appear to harm the fetus, according to one recent study. But for those who only use it to ease PMS, it may be worth eliminating while pregnant.

For others, stopping the medication could pose grave consequences. One patient was told by a doctor to give up their antidepressants, and halfway through the pregnancy they tried to commit suicide by jumping off a bridge and lost the baby, Niebyl says. "The issue boils down to whether the woman really needs to take it or not."

However, even less severe conditions like persistent headaches or allergies may warrant taking some medicine. No one has to grin and bear it if they're feeling lousy, experts say. "If it's of sufficient severity that it's interfering with their life, I would advise them to take something that I have reasonable confidence in being safe," says Pitkin.

In some cases, the choice of drug is critical, but in most others, something is available. "If a patient is taking a drug that should not be used during pregnancy, there usually are alternatives that are safe," Niebyl says.

ACE inhibitors used to treat high blood pressure, for example, can damage a baby's kidneys, but other blood pressure drugs don't. The same goes for antibiotics: tetracyclines cause tooth discoloration and delayed bone growth in babies, but other antibiotics, including penicillin, amoxicillin, and erythromycin, are safe to treat a range of conditions.

Timing may also make a difference. Acetaminophen is typically recommended instead of aspirin for pain relief, especially in the last trimester, because aspirin carries a greater risk of bleeding. Ibuprofen should be limited to no more than a day or two because prolonged use can affect fetal circulation.

In fact, one recent study of 22 women by researchers from the University of Texas M.D. Anderson Cancer Center in Houston even found that chemotherapy treatment for breast cancer in the second and third trimesters doesn't put babies at significant risk, despite widespread fears to the contrary. The study also showed that radical and partial mastectomies are safe treatments.

Sometimes the medications that are necessary still carry a risk of birth defects, such as the use of anti-convulsants to treat epilepsy. Doctors should counsel women that they have twice the risk of birth defects on these drugs, but in some cases it may be possible, at least in the first trimester, to withhold treatment, reduce the dosage or switch to a different anticonvulsant that reduces the risks.

But with any drug, even over-the-counter medications such as Tylenol, use caution and get an OK first from your doctor or midwife, particularly since you can't diagnose your own illness, Filkins says.

"I think there are medications that can be extremely helpful and can allow women to have a safer pregnancy, but there are many issues involved in terms of what can be taken safely and when, so it's very important to seek medical care."