Neonatal recurrent prolonged hypothermia associated with maternal mirtazapine treatment during pregnancy.

We present a case of recurrent hypothermia in concordant monozygotic twins born to a mirtazapine treated mother. The twins were born at 35 weeks gestation at birth weights of 2426 g and 2355 g. Both twins presented with recurrent hypothermia continuing until day 10 of life. Possible etiologies of hypothermia were excluded. The degree of prematurity and the weight of the twins were not consistent with prolonged thermal instability. The twins' mother was treated with mirtazapine during the entire pregnancy. Due to its serotonin and alpha 2 receptors antagonism mirtazapine is known to influence thermoregulation in adult humans and other mammals. We suggest that maternal mirtazapine treatment during pregnancy was associated with recurrent hypothermia in both identical twins.