Which Medicines Are Safe in Pregnancy?

Which Medicines Are Safe in Pregnancy?

It depends on the drug, on the timing during pregnancy and what you consider safe.

Are you pregnant (or considering getting pregnant) and taking a medicine regularly? If you have severe asthma, are diabetic, suffer from a mood disorder or any one of a number of chronic health challenges, you take probably take medicine for it. And you certainly worry about how that might affect your fetus.

I was asked to sit on a panel the FDA called to consider how to best help doctors explain the risks of taking medicines during pregnancy and how to help the expectant woman determine if the benefits of the medicine outweigh the risks to the fetus. Here is a link to the Risk Advisory Communications Committee on Pregnancy and Lactation Label rule. Here’s what I learned:

Baseline Risk

Every pregnancy is risky. A pregnant woman can do everything “right” and still something might turn out wrong.

Of the 6 million women who become pregnant each year, (about half of them unplanned!) as many as 20% will end in a miscarriage or stillbirth, most of those for no known reason. Of infants born to families with no known risks for birth defects, 3% with have a “congenital anomaly,” — a birth defect like cleft palate, spina bifida or any one of thousands of things that can go wrong. Some physically perfect babies will have grow up to have autism, bipolar disorder, epilepsy or any one of a million challenges. These are called “baseline” risks. Everyone has an equal risk because medical science hasn’t yet figured out why they happen.

Absolute Risk

Exposing a fetus to a drug by taking medicine increases the risk of a birth defect or later health problem. But most often the increased risk is very small.

Don’t listen to statistics that say “might double the risk of…” That’s called relative risk and it’s very deceptive. Here’s why: If the risk is 1 in 3,000,000 and you’ve doubled it, than the absolute risk is 2 in 3,000,000. That’s incredibly tiny! If a medicine is needed to save your life or mental health, that seems like a risk most people can live with.

Unfortunately, for most drugs medical science can’t give you such clear statistics. Very few drugs have been tested on pregnant women, despite the FDA ordering drug companies to do that.

How Much Do You Need that Medicine?

Pregnant women being treated for epilepsy, severe asthma, depression or other life-threatening disease have to carefully balance the increase over the baseline risk vs. the risk of not taking the medicine. You and your doctor won’t have all the information you will want to make that decision, but if you don’t need that medicine, or can use an alternative method for your health care during pregnancy and breastfeeding, it’s a good idea to consider that option carefully.

What Questions Should You Ask?

What are the most common harms to the fetus can this medicine cause?
What is the baseline risk?
What is the increased risk to the fetus if I take this medicine? Flip that number around, for example, if there is a 3% combined absolute risk of cleft palate, there is a 97% chance of a baby without a cleft palate.
What happens to my health if I don’t take this medicine?
Is that potential damage to my fetus something I can deal with? (Cleft palate can be surgically repaired. But if you have little health insurance and less money, it might be a disaster for your family)

Why Doctors Don’t Know

The FDA requires pharmaceutical companies to study the safety and effectiveness of many drugs on pregnant women (and/or children or other subgroups) after approval when the drug is on the market. In reality, very few of these post-marketing studies have been completed.

There are ethical problems with including pregnant women in a drug trial when the risk to the mother and fetus are unknown. But it creates a much worse ethical dilemma when doctors are forced to treating pregnant women with no information.

What do doctors do in this case? They make educated guesses. They consider how the drug works in the body, what other drugs work like that and have they caused harms? Then they make an educated guess. You, the pregnant woman, are the one who makes the final decision.

A final thought. If you are taking a drug in pregnancy and there is a pregnancy registry for that drug, please sign up! It’s the best indicator the FDA will get if something goes wrong. And it puts you on the list to know if the FDA has found a problem so that you can get the help you and your baby need.


Suzanne B. Robotti

Suzanne B. Robotti

Suzanne Robotti founded MedShadow Foundation in 2012. Learn more about Su and her mission.


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