, although the overall risk remains extremely low, a new study finds.
The findings were presented in a poster at the 50th annual meeting of the Child Neurology Society.
“Our work showed that neonates exposed to SSRI in utero had higher risks of neonatal encephalopathy even when adjusting for confounders such as maternal mental health disorders and age. SSRIs could cause side effects such as encephalopathy in neonates, and these risks need to be balanced carefully with the potential benefits of treatment to the mother,” study lead author Marie Cornet, MD, a neonatology fellow with Benioff Children’s Hospital at the University of California, San Francisco, said in an interview.
According to Dr. Cornet, “we know that SSRI exposure in utero is associated with increased risks of respiratory distress at birth, need for positive-pressure ventilation, and an abnormal neurologic exam.” The researchers launched the new study to determine if the estimated 4%-8% of pregnant women who take SSRIs may be putting their newborns at greater risk of NE.
The researchers retrospectively tracked 305,426 infants who were born in the Kaiser Permanente Northern California health system (≥35 weeks) from 2011 to 2019. The mothers had an average age of 31 years, and approximately 34.7% were White, 34.7% of unknown race, 23.3% Asian, and 6.2% Black.
The researchers defined NE as a “5-minute APGAR score <7 and abnormal level of consciousness, activity, tone, or reflexes.”
A total of 8,024 infants (2.6%) had mothers who used SSRIs in the third trimester, and 510 (0.17%) were determined to have had NE.
After adjustment for maternal depression or anxiety, maternal age, race, and hospital, exposed neonates had 2.7 times higher odds of NE (odds ratio, 2.7).
Each 25 mg per day increase in the dose of SSRIs, as equalized to doses of sertraline (Zoloft), was linked to a significant 31% increase in the odds of developing NE (OR, 1.31).
The study doesn’t examine the benefits of SSRI treatment in pregnancy. Those taking SSRIs were much more likely to have depression during pregnancy (76.5% vs. 13.5%) and anxiety (56.7% vs. 6.9%), compared with those who did not take the drug.
The possible connection between SSRIs and NE is unclear. “SSRIs may contribute to NE by a withdrawal mechanism or by a toxicity mechanism. It is also possible that SSRIs themselves are not responsible for encephalopathy, or that the severity of maternal mental health is itself responsible for increased neonatal encephalopathy,” Dr. Cornet said. “However, we believe we adjusted our results thoroughly for that. Furthermore, in this cohort, neonates born from mothers with untreated depression were not at higher risk of encephalopathy than neonates born to mothers without depression.”
She added: “When infants have acidosis or require prolonged resuscitation after birth, they get treated with therapeutic hypothermia. This invasive treatment was shown to decrease mortality and morbidity in neonates with hypoxic-ischemic encephalopathy. However, therapeutic hypothermia may not be helpful in infants with encephalopathy due to other causes than acute hypoxia-ischemia, such as infection, inflammation, genetic conditions, or exposure to toxins. In the case of SSRIs, our results show that, while neonates often have encephalopathy, this encephalopathy is often mild and self-resolved. We did not see a statistically significant increase in acidosis or treatment with therapeutic hypothermia.”
In the future neurologists should consider SSRI use as a potential cause in cases of NE, Dr. Cornet said. “If there are no signs of hypoxic-ischemic encephalopathy – no evidence of acidosis, acute perinatal event – treatment with therapeutic hypothermia may not be indicated.”
Dr. Cornet said more research is in the works. “Studying the long-term side effect of SSRIs on neonatal brain development and injury is essential,” she said. “We plan to compare brain injury in neonates exposed and unexposed to SSRIs and examine long-term outcomes to assess if the effect of SSRI exposure is transient or has a lasting impact.”
This study was funded by the Thrasher Early Career Research Grant and by the Newborn Brain Research Innovation Award at UCSF. The authors have no relevant disclosures.