ADHD meds in mothers linked to increased risks in newborns

Newborns whose mothers took attention-deficit/hyperactivity disorder (ADHD) medication while pregnant had slight to moderately increased risks for preterm birth, rate of admission to a neonatal intensive care unit (NICU), and frequency of central nervous system (CNS)-related disorders, according to a study by Swedish investigators recently published in Pediatrics.

“To our knowledge, this is the largest study to date in which perinatal outcomes after maternal use of prescribed ADHD medication during pregnancy are analyzed,” wrote investigators led by Ulrika Nörby, MSc Pharm, PhD, Health and Medical Care Administration, Stockholm County Council, Stockholm, Sweden. “Our results revealed weak to modest associations between in utero exposure to ADHD medication and neonatal morbidity.”

After adjusting for maternal factors, the researchers found no association between medication exposure and congenital malformations.

Use of ADHD medication has increased rapidly in the past decade in both the general population and pregnant women, the researchers noted. “In the United States, [about] 1% of pregnant women use drugs for treatment of ADHD, which ranks these medications among the most commonly used prescription drugs during pregnancy,” Dr. Nörby and colleagues wrote.

For this study, their goal was to investigate the perinatal outcomes of in utero exposure to prescribed ADHD medication. Using data from Swedish medical registries on 964,734 single-born infants, the researchers identified 1,591 newborns exposed to ADHD medication during pregnancy. About 90% of them were exposed to methylphenidate. The researchers identified another 9,475 infants whose mothers used ADHD medication before or after, but not during, pregnancy.

Then they compared infants exposed to ADHD medication in utero with those whose mothers used ADHD medication before/after pregnancy along with infants whose mothers never used these drugs.

Increased risk

After analyzing the data, the researchers found several notable results:

• Medication used during pregnancy increased the risk for NICU admission compared with both no medication use (adjusted odds ratio [aOR]: 1.5; 95% confidence interval [CI], 1.3-1.7) and medication use before/after pregnancy (aOR: 1.2; 95% CI: 1.1-1.4).
• Infants exposed to ADHD medication during pregnancy had increased frequency of CNS-related disorders (aOR: 1.9; 95% CI: 1.1-3.1) and were more often moderately preterm (aOR, 1.3; 95% CI: 1.1-1.6) than unexposed infants.
• Exposed infants were more frequently “large for gestational age” than unexposed ones (aOR: 1.3; 95% CI: 1.0-1.7)
• No increased risk for congenital malformations or perinatal death was identified

Although newborns exposed to ADHD medication in utero were more likely to be admitted to a NICU (for a median duration of 7 days), no individual neonatal diagnoses stood out, other than CNS-related disorders.

Similarly, respiratory symptoms were the most common diagnoses among the infants; however, after adjusting for maternal factors, the researchers found that infants exposed to ADHD drugs during pregnancy had no increased occurrence of respiratory problems.

“These findings warrant attention but are hardly reasons to abstain from ADHD medication during pregnancy if treatment is crucial for the woman,” Dr. Nörby and colleagues advised.

Characteristic differences

Interestingly, women who used ADHD medication had some noticeably different characteristics than women who didn’t. “Women treated with ADHD drugs were younger, more often [first-time mothers], smokers, obese, more frequently lived without the father of the child, and they also used other medications to a larger degree,” the researchers wrote.

It’s possible that these background differences between treated women and controls might explain, to some degree, the increased risk for infants exposed in utero.

“It is uncertain to what extent this can be explained by the ADHD medication per se,” the authors noted. They pointed to another study that suggested that symptoms of ADHD may result in an unhealthier lifestyle and increased maternal stress, which can ultimately affect the fetus or newborn.

“These factors must be taken into consideration and be carefully balanced against the potentially increased risk for neonatal morbidity associated with the drugs when decisions are made concerning treatment during pregnancy,” Dr. Nörby and colleagues concluded.