Background. In midpregnancy, more than 3000 women in Brno filled in the questionnaires for the ELSPAC study. They informed of their health, activities, stress and psychological state during this pregnancy. Methods and Results. Out of medical documentation, the results from routine prenatal examinations were extracted and records concerning all disorders occurred during the gravidity. After delivery, information comming from both sources were linked to the birth weight (BW) and gestational age (GA) data of newborns and analysis of variance was performed. In statistically significant relations the differences were stated in BW (grams) and in GA (weeks) between the group means and sample means for boys, girls and all newborns together. BW, GA or both values were significantly lower after taking some medicaments, alcohol drinking, in offsprings of mothers who felt feeble around the quickening, who worked part time, who were in leading position in their employments, who experienced serious disease, who tempted a suicide, who worried that the foetus might be handicapped in any way and who did not take their future motherhood for a priority. Heavier were newborns of women who married during pregnancy and longer GA had children of those who took folic acid. The relation of neurotic symptoms to the outcome of pregnancy was not found and stressogenic events showed only a limited effect on it. A strong deficit in BW and GA followed after premature abruption of placenta, after eclampsia, placenta praevia, cervical cerclage, partus premature imminens, bleeding in the 2nd trimester, hypertension and hospitalization, namely when repeated. BW only was lower with IUGR, oligohydramnion, and higher BW followed after oedemas. GA only was affected in those whose mothers omitted the sonographic examination and who were obliged to have a special diet. Conclusions. When newborns BWs were divided into 8 classes by 500 g and some maternal characters follow ed across the scale, significant trends were found in maternal heights, in all their weight indicators including maternal BW as well as in the weight gain in pregnancy, in the highest means found during pregnancy of systolic and diastolic blood pressures and in the lowest haemoglobin levels.

        Key words: birth weight, gestational age, risk factors, disorders of pregnancy, body size of mothers, activities in pregnancy, stress, neurotic symptoms, epidemiologic study.