Low Intelligence and Obstetric Complications

Abstract

Investigations into association between low intelligence and obstetric complications have been inconclusive. Dayton (1930) wrote that the litera ture on mental deficiency is replete in its references to difficult labour as an aetiological factor in production of intelligence defects. But in a retro spective inquiry he found no evidence that abnormal deliveries were associated more frequently with births of subnormal children. Pasamanick and Lilienfeld (1955) looked at birth records of sub normal children in Baltimore and concluded that the pre-natal and paranatal records of mentally defective children born in Baltimore between 1935 and 1952 showed significantly more complications of and delivery, prematurity, and abnormal neonatal conditions than a similar number of matched controls. The non-mechanical abnor malities such as bleeding during and toxaemia appear to be important factors in this association rather than mechanical factors of delivery previously described. Stott (1957) claimed that pregnancy troubles might be responsible for a large, and probably greater part of re tardation of subnormal children whom he was studying. Rauramo, Gronross, and Kivikoski (1961) obtained delivery reports of pupils in a school for backward children, and concluded that there was a raised incidence of forceps delivery, breech birth, toxaemia of pregnancy, and prolonged labour. It is difficult to assess results of these studies because they are based on comparisons between unrepresentative samples of subnormal children and control groups which do not seem adequate. These methodological difficulties were largely overcome by