PURPOSE After the increase of the prevalence of obesity in the German population as a whole the development of the mean weight of pregnant women and the somatic data of the corresponding newborns during the recent years need to be analyzed. MATERIAL AND METHODS The development of maternal age, weight and body mass index (BMI) at the beginning of pregnancy, and the weight and weight-length-index of the corresponding newborns was analyzed for the period from 1992 to 2000 by using data from the German Perinatal Survey. 2 880 283 mother-child pairs (single pregnancies only) were included in the study. The evaluation for the eastern (including Berlin) and western part of Germany was carried out separately. RESULTS The maternal weight (BMI) increased by 2 kg (0.4 kg / m 2 ) during this time interval. These changes seem to be primarily the result of an increase in the mean age of pregnant women by about two years, which could be observed within that period. In contrast to the increasing prevalence of obesity in the German population as a whole, the rate of obesity in pregnant women remained almost constant. During the examined period, the mean birth weight increased by 4 g per year (eastern Germany) and 5 g (western Germany). These data correspond very closely with those recently published for the north European countries and the USA. CONCLUSION In contrast to the German population as a whole the average weight of pregnants showed no significant increase between 1992 and 2000. Also the birth weight and derived indices remained nearly constant during this period.