Transient effects seen with in utero SSRI exposure

NEW YORK (Reuters Health) - Behavioral symptoms are common in newborns exposed in utero to selective serotonin reuptake inhibitors (SSRIs), a relatively new class of antidepressants that includes Prozac and Zoloft, and venlafaxine (Effexor) a new antidepressant with two modes of action, according to findings published in the journal Pediatrics. However, these effects appear to be transient and self-limited.

Dr. Ema Ferreira and colleagues from the University of Montreal, Quebec, Canada, examined the outcomes in a group of infants born to mothers taking SSRIs or venlafaxine during their third trimester and mothers who were not taking any antidepressants, psychotropic medications, or benzodiazepines at the time of delivery.

Outcome measures included infant behavioral signs defined by symptoms involving central nervous, respiratory, and digestive systems.

Included in the study were 76 mothers taking an SSRI or Effexor at the time of delivery and their 79 infants, and 90 unexposed mothers and their 91 infants.

Smoking, alcohol intake, and substance abuse were significantly more often seen in the mothers of exposed infants compared with the mothers of unexposed infants. Exposed mothers were also significantly more likely to have asthma, migraine and cesarean sections.

Among the exposed infants, "the signs most often observed involved the central nervous system (63.2 percent): tremors, shaking, agitation, spasms, hyper- or hypotonia (muscle spasticity and loss of muscle tone, retrospectively), irritability and sleep disturbances," Dr. Ferreira's team reports. There were symptoms involving the respiratory system (40.8 percent) as well as infants with rapid or slow heart beats.

All of these signs appeared during the first day of life, and the average duration was 3 days for exposed infants.

All premature infants who were exposed to the antidepressant agents exhibited behavioral manifestations, compared with about two thirds of exposed term infants. The average hospital stay was nearly four times longer for exposed preterm newborns than for unexposed preterm infants (14.5 days versus 3.7 days, respectively).

"Premature infants could be more susceptible to the effects of selective serotonin reuptake inhibitors and venlafaxine," the investigators conclude.

SOURCE: Pediatrics, January 2007.