Tricyclic antidepressants (TCAs) are the type of antidepressant most commonly prescribed to relieve pain. Studies of the effects of TCAs in pregnant women have not been conducted. However, some reports have suggested that newborns may suffer from muscle spasms and heart, breathing and urinary problems when their mothers take TCAs immediately prior to a child’s birth.

TCAs are known to pass into breast milk and may cause drowsiness in a nursing infant.

Selective serotonin and norepinephrine reuptake inhibitors (SSNRIs) also pass into breast milk and are not generally recommended when breastfeeding.

The U.S. Food and Drug Administration (FDA) cautioned in December 2005 that early results from new studies suggested that use of a selective serotonin reuptake inhibitor (SSRI), paroxetine (Paxil), during the first three months of pregnancy may increase the risk of heart defects and other problems in the baby. Recent research also suggests that use of SSRIs late in pregnancy might increase the infant’s risk of a serious lung condition called pulmonary hypertension of the newborn. 

In light of such findings, the American College of Obstetricians and Gynecologists issued a recommendation in 2006 that pregnant women not be treated with paroxetine and that other SSRIs and selective serotonin and norepinephrine reuptake inhibitors (SSNRIs) be used cautiously during pregnancy.  The benefits of these drugs to the individual patient must be considered when deciding whether to continue use of antidepressants during pregnancy and when breastfeeding is being considered.