['To assess the effect of a local guideline advising elective caesarean section without maternal comorbidity at a gestational age of >or= 39+0 weeks.', 'Retrospective cohort study.', 'Children born by elective caesarean section in the period 2003-2007 at the VUmc with a gestational age >or= 37+0 weeks and without maternal comorbidity were included. Respiratory complications, length of hospital stay, admission to the neonatal intensive care unit (NICU), respiratory support and medication were recorded from charts of admitted children. These data were compared with data collected in 1994-1998 before implementation of the local guideline.', 'In 2003-2007, 501 children were born from 486 elective caesarean sections. In 1994-1998, 333 children were born from 324 elective caesarean sections. In 2003-2007, mean maternal age was younger, local anaesthesia more frequent, elective caesarean section was more often performed at >or= 39+0 weeks (p < 0.001) and the birth weight was higher. In 2003-2007, fewer infants were admitted to an NICU than in 1994-1998 (6/501 versus 17/333, p < 0.001), of whom fewer infants were born with gestational age <or= 39+0 weeks (50% versus 94%, p = 0.04). In 2003-2007, respiratory morbidity was lower in the group with gestational age 38+0/7-38+6 weeks than in 1994-1998. This is explained by the higher number of elective caesarean sections performed at gestational age of 38+4/7-38+6 weeks in 2003-2007 (63%) compared with 1994-1998 (28%; p < 0.001). After correction for confounders, the odds ratio for developing respiratory morbidity in 2003-2007 was 0.27 compared with 1994-1998 (95% CI: 0.10-0.70).'] Is [ Less neonatal morbidity with elective caesarean sections at term : local guideline for elective caesarean section effective ]?