Study Group (number of patients) Anesthesia Procedure Study protocol Vasopressor Outcome measures Dyer et al. 2004 [11 ] Preload (25) (2) Coload (25)Spinal anesthesia Elective cesarean section 20 ml/kg modified Ringer’s lactate over 20 min before anesthesia (2) 20 ml/kg modified Ringer’s lactate by rapid infusion at time of CSF identificationEphedrine (5 mg) Hypotension, MAP, need for vasopressors, umbilical arterial pH, Apgar score, nausea and vomiting Farid et al. 2016 [14 ] Preload (37) (2) Coload (37)Spinal anesthesia Elective cesarean section 15 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 15 ml/kg Ringer’s lactate at time of anesthesia administrationEphedrine or phenylephrine (dose not provided) Hypotension, need for vasopressors Jain and Valecha 2017 [15 ] Preload (30) (2) Coload (30)Spinal anesthesia Elective cesarean section 15 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 15 ml/kg Ringer’s lactate over 20 min at time of CSF identificationEphedrine (3 mg) Hypotension, HR, SBP, Apgar score Khan et al. 2013 [16 ] Preload (50) (2) Coload (50)Spinal anesthesia Elective cesarean section 20 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 20 ml/kg Ringer’s lactate by rapid infusion at time of CSF identificationEphedrine (5 mg) Hypotension, HR, SBP, MAP, need for vasopressors, Apgar score Oh et al. 2014 [17 ] Preload (30) (2) Coload (30)Spinal anesthesia Elective cesarean section 15 ml/kg Ringer’s lactate by rapid infusion before anesthesia (2) 15 ml/kg Ringer’s lactate after intrathecal injectionEphedrine (5 mg) Hypotension, need for vasopressors, umbilical arterial pH, Apgar score, nausea and vomiting Rao and Vijaya 2015 [12 ] Preload (30) (2) Coload (30)Spinal anesthesia Elective cesarean section 15 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 15 ml/kg Ringer’s lactate by rapid infusion at time of CSF identificationEphedrine (6 mg) Hypotension, HR, SBP, MAP, need for vasopressors, Apgar score Sarkar et al. 2014 [18 ] Preload (50) (2) Coload (50)Spinal anesthesia Emergency cesarean section 15 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 15 ml/kg Ringer’s lactate over 20 min after anesthesiaEphedrine (3 mg) Hypotension, need for vasopressors, Apgar score Shah et al. 2015 [19 ] Preload (50) (2) Coload (50)Spinal anesthesia Elective cesarean section 10 ml/kg Ringer’s lactate over 15 min before anesthesia (2) 10 ml/kg Ringer’s lactate at time of CSF identificationEphedrine or phenylephrine (dose not provided) Hypotension, need for vasopressors Sharma et al. 2016 [20 ] Preload (60) (2) Coload (60)Spinal anesthesia Elective cesarean section 20 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 20 ml/kg Ringer’s lactate by rapid infusion after intrathecal injection Mephentermine (3 mg) Hypotension, need for vasopressors, SBP Williams et al. 2012 [21 ] Preload (50) (2) Coload (50)Spinal anesthesia Elective cesarean section 15 ml/kg Ringer’s lactate over 20 min before anesthesia (2) 15 ml/kg Ringer’s lactate over 20 min at time of CSF identificationEphedrine (3 mg) Hypotension, HR, SBP, umbilical arterial pH, Apgar score, nausea and vomiting