A 2-phase study assessing the impact of obesity and increasing maternal age on caesarean section rates was performed. Phase 1 was retrospective and involved comparing caesarean section rates in spontaneously labouring nullipara and spontaneously labouring nullipara weighing 60-80 kg and aged 20-35 (standard nullipara), delivering between 1992 and 2006. In the 15 years studied there was a rise in the caesarean section rate from 6.5% to 19.0%, although the increase was less marked in the standard nullipara (4.8-15.5%). Phase 2 was prospective and involved collecting delivery data of singleton cephalic nullipara spontaneously labouring at term. The data of 126 women was collected of whom 99 were non-obese and 27 were obese. Statistical analysis compared the delivery outcomes between the two groups and showed that obese women were 5.82 times more likely to have a caesarean section compared with non-obese women. This finding was highly statistically significant (p = 0.005).