Caesarean section (CS) rates are increasing in many parts of the world, recently reaching about 20% worldwide. The postmodern lifestyle characteristics, obesity and delayed childbirth, have been put forward as the main reasons for high CS rates. The present study tests the association patterns between lifestyle parameters and delivery mode on a data set of 3786 births in Vienna between 2005 and 2013. The focus is exclusively on singleton term births. As well as maternal age, prepregnancy weight status, maternal body height and gestational weight gain, newborn size (birth weight, birth length, and head circumference), Apgar scores and child presentation were recorded. Planned as well as emergency CS rates increased significantly (p < 0.0001) with increasing maternal age and decreasing maternal body height. Emergency CS rates, however, increased significantly with increasing maternal prepregnancy weight status and gestational weight gain. An especially high risk of emergency CS occurred among four groups of mothers: those older than 40 years (OR = 2.68; 95% CI 1.87⁻3.86), those who were obese (OR = 1.44; 95% 1.15⁻1.81), those experiencing a gestational weight gain above 15 kg (OR = 1.32; 95% CI 1.13⁻1.54), and those shorter than 160 cm (OR = 1.216; 95% CI 1.02⁻1.45). Emergency CS rates were significantly higher among low-weight newborns (<2500 g) and macrosome newborns (>4000 g) than among normal-weight newborns. Furthermore, breech presentation was associated with an increased risk of caesarean delivery (OR 6.97; 95% CI 6.09⁻7.96). Logistic regression analyses reveal that maternal age, maternal body height, prepregnancy weight status, gestational weight gain, birth weight, newborn head circumference and child presentation show an independent, highly significant association with caesarean delivery. We conclude that maternal and newborn characteristics typical of recent lifestyle patterns, such as advanced maternal age, obesity, increased gestational weight gain and increased newborn size, are highly significantly associated with increased emergency CS rates. Moreover, maternal shortness and breech presentation are risk factors for emergency CS.
Keywords: caesarean section rates; child presentation; delivery mode; macrosomia; maternal age; maternal height; newborn size; obesity; recent environment.