Background: Selective serotonin reuptake inhibitors (SS- RIs) have been associated with withdrawal symptoms. We investigated whether use of these drugs in pregnant women might cause neonatal withdrawal syndrome. Methods: An association between paroxetine and neonatal convulsions was identified in December, 2001, by the data mining method routinely used to screen the WHO database of adverse drug reactions. An information component (IC) measure was used to screen for unexpected adverse reactions relative to the information in the database. We then assessed cases of neonatal convulsions and neonatal withdrawal syndrome associated with drugs included in the anatomical therapeutic chemical groups N06AB and N06AX. Findings: By November, 2003, a total of 93 suspected cases of SSRI- induced neonatal withdrawal syndrome had been reported, and were regarded as enough information to confirm a possible causal relation. 64 of the cases were associated with paroxetine, 14 with fluoxetine, nine with sertraline, and seven with citalopram. The IC- 2 SD for the group became greater than 0 in the first quarter of 1991, and the IC increased to 2.68 (IC- 2 SD 0.32) by the second quarter of 2003. For each individual compound, the IC- 2 SD was greater than 0. Interpretation: SSRIs, especially paroxetine, should be cautiously managed in the treatment of pregnant women with a psychiatric disorder. We investigated whether use of these drugs in pregnant women might cause neonatal withdrawal syndrome. Methods: An association between paroxetine and neonatal convulsions was identified in December, 2001, by the data mining method routinely used to screen the WHO database of adverse drug reactions. An information component (IC) measure was used to screen for unexpected adverse reactions relative to the information in the database. We then assessed cases of neonatal convulsions and neonatal withdrawal syndrome associated with drugs included in the anatomical therapeutic chemical groups N06AB and N06AX. Findings: By November, 2003, a total of 93 patients cases of SSRI-induced neonatal withdrawal syndrome had been reported, and were viewed as enough information to confirm a possible causal relation. 64 of the cases were associated with paroxetine, 14 with fluoxetine, nine with sertraline, and seven with citalopram. The IC-2 SD for the group became greater than 0 in the first quarter of 1991, and the IC increased to 2.68 (IC-2 SD 0.32) by the second quarter of 2003. For each individual compound , the IC-2 SD was greater than 0. Interpretation: SSRIs, especially paroxetine, should be cautiously managed in the treatment of pregnant women with a psychiatric disorder.