Source: Cancer  |  Posted 7 years ago

Neonatal in utero exposure to antidepressants taken for maternal anxiety and depression is significant, and may precipitate short-term adverse effects in neonates after birth.

Neonatal serotonin toxicity, the term used for short-term adverse effects of fluoxetine and paroxetine taken during the antenatal period on neonates, has been described in previous studies.

Investigating a potential relationship between the extent of neonatal in utero antidepressant exposure and well-being after birth, Dr. Jonathan Rampono of the Department of Psychological Medicine, King Edward Memorial Hospital, Subiaco, Western Australia, and colleagues studied a cohort of 11 women in the last trimester of pregnancy who were taking antidepressant medications.

Four women were taking fluoxetine, 4 sertraline, 2 paroxetine, and 1 venlafaxine. All had clinically established steady-state antidepressant concentrations prior to delivery.

Antidepressant assays were performed using venous blood serum collected from the mother in the first stage of labour, the umbilical cord soon after delivery, and infant heel on day 5 after birth. Neonatal well-being was determined by gestation age, birth weight, Apgar score at birth, and Neonatal Abstinence Scores (NAS) on each of the first 3 days postpartum.

A significant in utero exposure was observed for all drugs tested, with cord:maternal serum ratios being a mean of 0.52 for paroxetine, and a median of 0.67 for sertraline, 0.63 for N-desmethylsertraline (metabolite), 0.67 for fluoxetine, 0.72 for norfluoxetine (metabolite), 1.1 for venlafaxine (single case), and 1 for O-desmethylvenlafaxine (metabolite, single case).

At birth, children were on average 38 weeks of gestational age and weighed 2.88 kg, with generally good to excellent Apgar scores. NAS scores were mildly increased for half of the neonates exposed to fluoxetine, and in 1 twin exposed to paroxetine. Only fluoxetine and norfluoxetine were measurable in day 5 infant serum samples.

Based on their results, Dr. Rampono and colleagues hypothesise that low clearance of antidepressants may predispose neonates to 'neonatal serotonin toxicity,' and recommend further study in a larger population.