Objectives: In perinatal medicine, morbid (severe) obesity of the mother occurs in approx. 1% of cases and is gaining in importance, even more so when considering the rising trend of juvenile adiposity. This retrospective cohort study aims at characterising high-risk pregnancies associated with morbid obesity (BMI ‡ 40). Along with epidemiologic insights, the analysis purveys clinically relevant results useful for developing guidelines regarding preconceptional and pregnancy care in morbid obesity. Methods: Perinatal statistics from eight German federal states of the years 1998 -2000 (n = 508 926 singleton pregnancies) were analysed. Pregnant women with coexistent morbid obesity were stratified into two groups -group 1: BMI 40.00 -44.99; n = 3188 (0.6 %) and group 2: BMI ‡ 45.00; n = 787 (0.2 %) -and compared to a reference population with a BMI between 18.50 and 24.99 (n = 320148) with regards to gestational, perinatal and neonatal risks. Weight percentiles were used to classify the neonates according to size (hypotrophy if < 10th, hypertrophy/fetal macrosomia if > 90th). c 2 -Test was used to test for significance of results. Due to the large sample size, all differences between the control group (BMI: 18.50 -24.99) and the group of morbidly obese pregnant women (BMI ‡ 40) were highly significant (p < 0.001). Results: The obtained risk profile for morbidly obese pregnant women primarily shows pregnancy related diseases, such as hypertension, preeclampsia and gestational diabetes. Hypertension occurred in 1.2 % of controls, whereas it occurred in 17.1% (BMI = 40.00 -44.99) and 23.3 % (BMI ‡ 45) with morbid obesity. Signs of fetal hypoxemia were found in 21.1% of controls vs. 30.9% (group 1), and 33.9 % (group 2) respectively, of obese women. At a BMI ‡ 45 (25.9 %), 38.4 % underwent caesarean sections. HypertroZusammenfassung ! Fragestellung: In der Perinatalmedizin gewinnt die Adipositas permagna (morbide Adipositas) mit einer Häufigkeit von ca. 1 % auch aufgrund der steigenden Inzidenz der juvenilen Adipositas zunehmend an Bedeutung. In einer retrospektiven Kohortenstudie wird die Risikoschwangerschaft Adipositas permagna (BMI ‡ 40) charakterisiert. Die Datenanalyse liefert neben epidemiologischen Erkenntnissen auch praxisrelevante Ergebnisse für die Erstellung von Empfehlungen zur präkonzeptionellen und Schwangerenberatung bei Adipositas permagna. Populationsstudie: Die in der Kohortenstudie verwendeten Daten stammen aus 8 Bundeslän-dern Deutschlands der Jahre 1998 -2000 (n = 508 926 Schwangere mit Einlingsgeburten). Schwangere mit einer Adipositas permagnaGruppe 1: BMI 40,00 -44,99; n = 3188 (0,6%) und Gruppe 2: BMI ‡ 45,00; n = 787 (0,2%) -wurden mit einer Normalpopulation mit einem BMI 18,50 -24,99 (n = 320148) hinsichtlich Schwangerschafts-, Geburts-und Neugeborenenrisiken verglichen. Die somatische Klassifikation der Neugeborenen erfolgte entsprechend der 10. Gewichtsperzentile (Neugeborenen-Hypotrophie) und der 90. Perzentile (Neugeborenen-Hypertrophie, fetale Makrosomie). Der c 2 -Test diente zur Signif...