Investigators hypothesized that the impact of surgery in terms of inducing a hypercoagulable state is more evident in morbidly obese pregnant women as opposed to their non-obese counterparts. The aim of this study is to investigate the change in coagulation status of morbidly obese and non-obese pregnant women following cesarean section delivery using thromboelastometry. This observational study would also make it possible to calculate the sample size for a future prospective controlled clinical trial to compare the incidence of Hypercoagulability in morbidly obese parturients as opposed to their non-obese counterparts. To the best of our knowledge, no other work has been done any in this area.

Following institutional ethical committee approval, 20 morbidly obese (BMI>40) and 20 non-obese (BMI < 30) parturients undergoing elective low segment cesarean section (LSCS) delivery under spinal subarachnoid block will be recruited into the study. A written informed consent will be obtained from all parturients prior to inclusion. All patients will receive an information sheet at the preoperative assessment visit to inform them about this study. Patients with a history of past or current thromboembolism will be excluded from the study as well as those with liver disease and those already on anticoagulant/anti-platelet therapy for repeated miscarriage or other indications. History of thromboembolism is defined as an arterial or deep venous thrombosis, catheter thrombosis, or pulmonary embolism diagnosed by ultrasound or spiral computed tomography (CT). Preoperative baseline full blood count and clotting profile will be done. Parturients with abnormal platelet count or coagulation results and those who will need conversion to general anesthesia will be excluded.

Data and sample collection Preoperative BMI, co-existing morbidities and laboratory test results including INR, PTT and platelet count as well as operative time and postoperative clinical or radiological evidence of thromboembolism will be recorded. A blood sample will be collected for ROTEM analysis prior to establishing the block (baseline), immediately after surgery and 8 hours later.

ROTEM analysis

Coagulability will be assessed using the ROTEM thromboelastometry analyzer (The ROTEM® delta, Tem Systems Inc.®, Munich, Germany). Extrinsic rotational thromboelastometry (EXTEM), intrinsic rotational thromboelastometry (INTEM) and FIBTEM will be measured for each blood sample. Clotting time (CT), clot formation time (CFT) and maximum clot firmness (MCF) will be recorded. Total clot strength will be assessed by "G" value as calculated according to the formula: (5000xMCF)/100-MCF and expressed as dynes/cm2 . G has been shown to be valuable in diagnosing hypo- and hypercoagulability . In non-obstetric cohorts, hypercoagulability was defined as a G value of ≥ 11.7 dynes/cm2 and hypocoagulability as a G value of <5.0 dynes/cm2 (values provided by manufacturer).

Inclusion Criteria:

• pregnant women at term presenting for cesarean section under spinal anaesthesia with BMI less than 30 and more than 40

Exclusion Criteria:

• Patients with BMI between 30 and 40 BMI
• Patients with a history of past or current thromboembolism.
• Patients with history of liver disease and those on anticoagulant/anti-platelet therapy
• Patients who requires perioperative blood transfusion
• Patients having General anaesthesia

Term pregnant women presenting for elective cesarean section under spinal anaesthesia

No plan