The risk of caesarean section in obese women analysed by parity.

Abstract

OBJECTIVE: This study looked at the association between caesarean section (CS) and Body Mass Index (BMI) in primigravidas compared with multigravidas. STUDY DESIGN: We enrolled women at their convenience, in the first trimester after an ultrasound examination confirmed an ongoing pregnancy. Weight and height were measured digitally and BMI calculated. After delivery, clinical details were again collected from the Hospital's computerised database. RESULTS: Of the 2000 women enrolled, there were 50.4% (n=1008) primigravidas and 49.6% (n=992) multigravidas. Of the 2000 8.5% were delivered by elective CS and 13.4% were delivered by emergency CS giving an overall rate of 21.9%. The overall CS rate was 30.1% in obese women compared with 19.2% in the normal BMI category (p<0.001). In primigravidas the increase in CS rate in obese women was due to an increase in emergency CS (p<0.005) and in multigravidas the increase was due to an increase in elective CS (p<0.01). In obese primigravidas 20.6% had an emergency section for fetal distress. In obese multigravidas 17.2% had a repeat elective CS. CONCLUSION: The influence of maternal obesity on the increase in CS rates is different in primigravidas compared with multigravidas.