Placental passage of tricyclic antidepressants.

The use of antidepressants during pregnancy continues to garner considerable attention, though there are limited investigations that have sought to quantify fetal exposure. Maternal and umbilical cord sera were collected at delivery from ten women taking nortriptyline and seven taking clomipramine. Placental passage was calculated as the ratio of umbilical cord to maternal serum concentration. Obstetrical outcome data were gathered from subjects at delivery. The placental passage ratio of nortriptyline and its active metabolite, cis-10-hydroxynortriptyline, were .68 +/- .40, 1.40 +/- 2.40, respectively. Clomipramine and desmethylclomipramine ratios were .60 +/- .50, .80 +/- .60. Obstetrical complications, such as pre-term delivery and pregnancy induced hypertension, were increased compared to the national average. The in vivo ratios of umbilical cord to maternal serum drug concentrations demonstrate considerable fetal exposure and differ greatly from previous results utilizing ex vivo perfusion.