Acetaminophen (brand name Tylenol) is one of the most widely used pain relievers, including among pregnant women.
Research published in the journal American Family Physician even called acetaminophen “the pain reliever of choice during pregnancy,” and U.S. Centers for Disease Control and Prevention data suggest 65 percent of pregnant women use the drug.
Acetaminophen was most commonly used to treat pain, fever and flu symptoms among pregnant women in a recent study led by the Norwegian Institute of Public Health in Oslo.
However, it’s generally best to avoid any medications during pregnancy, including acetaminophen, unless they’re absolutely necessary.
When used during pregnancy, even this “safe” over-the-counter (OTC) drug, researchers found, may be associated with an increased risk of asthma in children.
Prenatal Acetaminophen Exposure Linked to Asthma
Researchers analyzed data from the Norwegian Mother and Child Cohort Study, which includes 114,500 mother/child pairs. Both prenatal acetaminophen exposure and use of acetaminophen during infancy were associated with an increased risk of asthma at ages 3 and 7.
Children whose mothers had used acetaminophen during pregnancy were 13 percent more likely to develop asthma by age 3, and the more acetaminophen used by the mother, the greater the risk became.
The study also looked into whether the reasons behind acetaminophen use (pain, fever and flu) could be causing the asthma link, but the association remained even after accounting for these factors.
Women who reported using acetaminophen for more than one reason during pregnancy had children with the greatest risk of asthma at age
The researchers did not recommend that pregnant women or infants stop using acetaminophen, even though past research has also suggested an asthma connection.
For instance research published in Pharmacoepidemiology and Drug Safety in February 2016 also found acetaminophen use during pregnancy was associated with a modest increased risk for offspring asthma.
Are Pain Relievers Safe During Pregnancy?
The findings raise questions about whether this widely used OTC medicine is actually as safe during pregnancy as women are being told.
Due to recent reports questioning the safety of prescription and OTC medicines when used during pregnancy, the U.S. Food and Drug Administration (FDA) recently looked into the issue. They looked into data regarding three widely used types of pain medications and potential associated side effects:
- Prescription nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of miscarriage
- Opioids and the potential risk of birth defects of the brain, spine or spinal cord
- Acetaminophen and the risk of attention deficit hyperactivity disorder (ADHD)
The FDA ruled that available data “prevented us from drawing reliable conclusions,” and they decided to keep their recommendations on how pain medicines are used during pregnancy the same at this time. However, it’s best to err on the side of caution when possible.
Acetaminophen Use During Pregnancy Linked to ADHD in Children
The findings raise questions about whether this widely used OTC medicine is actually as safe during pregnancy as women are being told.
Due to recent reports questioning the safety of prescription and OTC medicines when used during pregnancy, the U.S. Food and Drug Administration (FDA) recently looked into the issue. They looked into data regarding three widely used types of pain medications and potential associated side effects:
- Prescription nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of miscarriage
- Opioids and the potential risk of birth defects of the brain, spine or spinal cord
- Acetaminophen and the risk of attention deficit hyperactivity disorder (ADHD)
The FDA ruled that available data “prevented us from drawing reliable conclusions,” and they decided to keep their recommendations on how pain medicines are used during pregnancy the same at this time. However, it’s best to err on the side of caution when possible.
Acetaminophen Use During Pregnancy Linked to ADHD in Children
The potential link between prenatal acetaminophen exposure and ADHD came to light in 2014 after a study was published in JAMA Pediatrics.
It included data from more than 64,000 mothers and children in the Danish National Birth Cohort. Over 50 percent of the women reported taking acetaminophen while pregnant, which was found to be linked to:
- A 30 percent increased risk for ADHD in the child during the first seven years of life
- A 37 percent increased risk of being diagnosed with hyperkinetic disorder (HKD), a severe form of ADHD
Behavioral effects appeared to be dose dependent. The more frequent the use of acetaminophen during pregnancy, the higher the offspring’s chances of being diagnosed with ADHD-related problems.
Children of women who used the drug for 20 or more weeks during pregnancy had nearly double the risk of getting an HKD diagnosis. They also had a 50 percent greater chance of being prescribed an ADHD medication.
The researchers noted that “[r]esearch data suggest that acetaminophen is a hormone disruptor, and abnormal hormonal exposures in pregnancy may influence fetal brain development. As further reported by Forbes.
“Acetaminophen can cross the placenta, making its way to the fetus and its delicate developing nervous system. The drug is a known endocrine (hormone) disrupter, and has previously been linked to undescended testes in male infants.
Since the maternal hormone environment plays a critical role in the development of the fetus, the authors say that it’s ‘possible that acetaminophen may interrupt brain development by interfering with maternal hormones or via neurotoxicity such as the induction of oxidative stress that can cause neuronal death.’”
Prenatal Acetaminophen Exposure May Be Linked to Fertility Problems, Cancer in Boys
Along with asthma and ADHD, prenatal acetaminophen exposure appears to cut levels of testosterone in the womb, at least according to a study in mice. The animals were given doses of acetaminophen equivalent to a human dose.
While treatment for just one day did not affect testosterone levels, treatment three times a day for seven days did, cutting testosterone levels in the mice nearly in half. The finding is concerning, since most common male reproductive disorders are linked to lower testosterone exposure in fetal life.
It’s thought that acetaminophen’s interference with the development of the male reproductive system could not only lead to genital birth defects but also to infertility and testicular cancer.
Unlike the U.S. FDA, which has refused to warn pregnant women about potential risks, The Royal College of Midwives suggested pregnant women talk to their health care providers before taking acetaminophen.
The Royal College of Pediatrics and Child Health said that prolonged use of the drug should be avoided by pregnant women. Carmel Lloyd of the Royal College of Midwives told the Daily Mail:
“Ideally, women should avoid taking medicines when they are pregnant, particularly during the first three months … Minor conditions such as colds or minor aches and pains often do not need treating with medicines.”
While the mouse study suggested only male fertility may be affected, a separate study published in Scientific Reports revealed that acetaminophen (or NSAID) use in pregnancy could also potentially affect fertility of resulting daughters and granddaughters.
Vitamin D-Rich Foods During Pregnancy Decrease Risk of Allergies in Children
A higher intake of vitamin-D-rich foods during pregnancy has been linked to a lower risk of allergies in children. The study found for each 100 IUs per day of food-based vitamin D intake during the first and second trimesters (equivalent to the amount of vitamin D in an 8-ounce serving of milk) was associated with about a 20 percent lower risk of developing allergies by school age.
In this case, the use of supplemental vitamin D was not associated with the benefit, although it’s unclear what type of supplemental vitamin D was studied. Other research suggests that vitamin D deficiency may be a primary underlying cause of asthma. Vitamin D will also help to upregulate your immune system, which may explain its potential role in allergies.
