A study of the risk of mental retardation among children of pregnant women who have attempted suicide by means of a drug overdose

BACKGROUND The aim of the study was to estimate the effect on the fetal development of high doses of prescription drugs taken as a suicide attempt during pregnancy. METHODS Pregnant women were identified among self-poisoned females in the toxicological inpatient clinic in Budapest between 1960 and 1993. Congenital abnormalities, intrauterine development based on birth weight and post-conceptional age, mental retardation, cognitive-behavioral status were compared in exposed children born to mothers who had attempted suicide by means of a drug overdose during pregnancy with their siblings, born either before or after the affected pregnancy, as sib controls. RESULTS Of a total of 1 044 pregnant women, 74 used the combination of amobarbital, glutethimide and promethazine (Tardyl®, one of the most popular drugs for treatment of insomnia in Hungary) for suicide attempt. Of these 74 women, 27 delivered live-born babies. The mean dose of Tardyl® used for suicide attempts was 24 times the usually prescribed clinical dose. The rate of congenital abnormalities and intrauterine retardation was not higher in exposed children than in their sib controls. However, of the 27 exposed children, eight (29.6%) were mentally retarded (X²₁=79.7, p= Sig) while mental retardation did not occur among 46 sib controls. These exposed children were born to mothers who attempted suicide with Tardyl® between the 14th and 20th post-conceptional weeks. The components of Tardyl® used separately for a suicide attempt during pregnancy were not associated with a higher risk of mental retardation. Therefore the high doses of Tardyl® associated with the high risk for mental retardation may be due to the interaction of its three drug components. CONCLUSIONS The findings of the study showed that the high doses of a drug containing three components may be associated with a significantly increased risk for mental retardation without any structural defects, whereas each of these three component drugs taken alone was not associated with this adverse effect.