Obesity has become one of the most common risk factors in obstetric practice with serious anaesthetic implications. Obese pregnants have limited physiological reserves and cardiovascular co- morbidities when compared to non-obese pregnant women. Spinal anaesthesia is the anaesthetic technique of choice for caesarean section. The haemodynamic changes associated with spinal anaesthesia pose the greatest hazard to the mother and the foetus and are exaggerated in obese pregnant women. However differences in the changes in haemodynamic variables such as cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) between obese and non-obese pregnant women having caesarean section (CS) under spinal anaesthesia have not been studied before. This study compares the haemodynamic changes after spinal anaesthesia for CS in non-obese and obese parturients in a single centre, prospective case control study, using LiDCOrapidV2. This LiDCOrapidV2 device is a noninvasive method of measuring haemodynamic variables. It is a single centre, prospective, case control study. The primary outcome compares the differences and variability in CO, SV and SVR between obese and non-obese parturients. The secondary outcomes include comparison of the correlation between changes in blood pressure (BP) and CO in each patient and the difference in BP between conventional intermittent oscillometric device and continuous LiDCORapidV2in each patient with a view to assess the need for measurement of cardiac output in obstetric anaesthesia