On the basis of 24 maternity hospital records, the current study investigated the validity of maternal recall and the relationship of maternal infections during pregnancy and obstetric complications (OCs) to different diagnostic subgroups of endogenous psychoses on which we reported previously in this journal. Maternal recall showed good agreement to maternity hospital records in the Lewis and Murray scale (ϑ = 0.74). With regard to infectious diseases during pregnancy maternal recall and records showed a weaker, but also good correlation (ϑ = 0.18). Psychoses with low genetic loading had more OCs than psychoses with high genetic loading. Maternal infectious diseases, especially during the fourth or fifth month of gestation, were significantly allocated to Leonhard's systematic schizophrenias. Data from maternity hospital records support our report that infectious diseases during midgestation and further perinatal complications seem to be important etiologic factors in systematic forms of schizophrenia without marked familial loading.

This study aims to assess the validity of maternal recall for several perinatal variables 8–10 years after pregnancy in a twin sample. Retrospective information was collected 8–10 years after the delivery event in a cohort of mothers from the University of Southern California Twin Study (N = 611) and compared with medical records for validity analysis. Recall of most variables showed substantial to perfect agreement (κ = 0.60–1.00), with notable exceptions for specific medical problems during pregnancy (κ ≤ 0.40) and substance use when mothers provided continuous data (e.g., number of cigarettes per day; r ≤ 0.24). With the exception of delivery method, neonatal intensive care unit admission, birth weight, neonatal information, and post-delivery complications were also recalled with low accuracy. For mothers of twins, maternal recall is generally a valid measure for perinatal variables 10 years after pregnancy. However, caution should be taken regarding variables such as substance use, medical problems, birth length, and post-delivery complications.