Acetaminophen risk in pregnancy: What patients need to know

December 14, 2021

A pregnant woman holding a glass of water and a pill. — Talk with your doctor before taking acetaminophen while pregnant.

One of the things I love most about the medical community is our desire to continually find better answers and care methods through research. But occasionally, sharing the findings of a new study can lead to unnecessary concern and confusion – particularly if the results are not clearly communicated.

Such is the case with recent recommendations on acetaminophen use during pregnancy. Acetaminophen, also called paracetamol, is a mild pain-relieving drug commonly found in over-the-counter pain and cold medications such as Tylenol. It has generally been considered safe to use during pregnancy.

But in September 2021, a consensus statement urging caution on the use of acetaminophen during pregnancy was published in Nature Reviews Endocrinology.

Drafted by an international team of obstetricians, pediatricians, neurologists, and scientists with expertise in fetal development, toxicology, and endocrinology, the statement specifically recommends that pregnant patients:

Do not take acetaminophen, unless medically indicated
Consult with their provider if unsure about taking acetaminophen
Take the smallest dose for the shortest time

These guidelines are no different from what we’ve already been telling patients. Whether we’re prescribing medication or performing ultrasounds, our advice during prenatal care is always to use the least amount of exposure (to any drug or sound waves) to get the necessary benefits.

The authors based their statement on recent studies suggesting that acetaminophen could potentially harm a pregnancy. Understandably, this has caused a wave of concern among pregnant patients – 80% of whom report taking at least one medication while pregnant, with acetaminophen accounting for 65% of medications used.

However, many national Ob/Gyn organizations say there is no evidence to indicate concern.

What prompted the new statement on acetaminophen use?

Previously, the U.S. Food and Drug Administration (FDA) had labeled acetaminophen as “Category B,” meaning no studies had demonstrated it caused birth defects in animals. Like many medications, no specific studies involving pregnant women were performed.

Recent research suggests that prenatal exposure to acetaminophen might alter fetal development and increase the risks of certain neurodevelopmental, reproductive, and urogenital disorders.

Acetaminophen can cross the placenta, meaning it can enter the fetal bloodstream through a patient’s blood when they take the medication. While this was considered harmless in the past, there’s now concern that acetaminophen could act as an endocrine disruptor, potentially interfering with hormonal processes that influence the development of the baby’s nervous and reproductive system.

In some animal studies, acetaminophen exposure was associated with:

Reduced androgens – hormones that fuel the growth and development of “male” reproductive characteristics
Irregular development of ovaries

Epidemiologic studies, which analyze patterns and causes of certain conditions in specific populations over a designated time period, also have indicated an association between prenatal acetaminophen exposure and reproductive or nervous system abnormalities.

Scientists observed the reproductive development of several children across the globe whose mothers had taken acetaminophen during pregnancy. Some studies suggested that:

Male children within this group had a higher likelihood of being born with undescended testicles.
Female children were more likely to experience early puberty.
Children of both sexes had an increased risk of behavioral abnormalities such as attention deficit hyperactivity disorder (ADHD).

However, many studies showed no correlation. Those that did were limited by factors such as patient self-reporting and residual confounding – additional factors that could have affected the study results but were not considered.

Professional medical societies’ response

The American College of Obstetricians and Gynecologists (ACOG) says its guidance on acetaminophen use during pregnancy remains the same: Using acetaminophen is safe during pregnancy after talking with your provider because there is no clear evidence of a direct relationship between acetaminophen and irregular fetal development.

ACOG’s published response to the consensus statement also noted concern about the lack of options for safe pain relievers for pregnant patients.

The Society for Maternal-Fetal Medicine has not issued a direct response to the statement. But in 2017, its Publications Committee published its own review of articles relating to neurodevelopmental outcomes, especially ADHD, in children exposed in utero to acetaminophen. They agreed there was insufficient evidence of a causal relationship between these disorders and prenatal acetaminophen exposure.

What should patients do?

At UT Southwestern, we recommend that pregnant patients continue to use acetaminophen as medically necessary. Potential side effects might depend on the dosage amounts, so short-term use is generally safer than long-term use.

Reduce the use of multi-symptom treatments for cold and flu, and take only the type of medication you need. For example, if you don’t have a fever but you have a stuffy nose, take an antihistamine only – not a combination drug with fever-reducing acetaminophen.

To manage long-term pain, discuss alternative therapies with your provider. From acupuncture to yoga, some non-drug treatments can provide safe chronic pain relief during pregnancy.

Before taking medication for any type of pain, discuss it with your doctor to ensure you’re on the same page and making well-informed decisions. Our Ob/Gyn team is on top of the latest research and only recommends treatment or medication considered safe for both you and your baby.

To visit with an Ob/Gyn about pain relief options during pregnancy, call 214-645-8300 or request an appointment online.