Cesarean section is one of the most commonly performed surgical procedures; approximately 80-90% of elective cesarean sections are conducted using spinal anesthesia . Spinal anesthesia is the preferred technique for Cesarean Section (CS) due to its simplicity, reliability, low rates of airway complications, facilitation of postoperative analgesia, less neonatal exposure to potentially depressant drugs, to awake mother at the time of the birth of the child that establishes maternal-infant bonding and successful breastfeeding, and due to its low cost as compared to the general anesthesia . The chance of significant maternal hypotension is greater with spinal anesthesia than with epidural anesthesia. Left uterine displacement with appropriate administration of fluids and use of vasopressor medications can minimize the associated hypotension. Intravenous administration of crystalloid or colloid can reduce the degree of hypotension after spinal anesthesia for cesarean delivery.

Maternal hypotension is a frequent side effect of spinal anesthesia for cesarean delivery and it causes dangerous maternal and fetal effects . Maternal hypotension decreases uteroplacental circulation and it results in nausea, vomiting, bradycardia and different systems dysfunction particularly in the presence of other diseases as renal, hepatic, cardiac and neurological. Anesthesiologists should not allow hypotension to continue, this often requires the use of vasopressors to maintain blood pressure as ephedrine, phenylephrine and norepinephrine .

Cardiac output is the amount of blood pumped by the heart per unit of time and is determined by four factors: two factors that are intrinsic to the heart-heart rate and myocardial contractility-and two factors that are extrinsic to the heart -preload and afterload. Heart rate is defined as the number of beats per minute and is mainly influenced by the autonomic nervous system. Increases in heart rate escalate cardiac output if ventricular filling is adequate during diastole .

Atropine is an anticholinergic agent with its ability to treat bradycardia both in mother and fetus. Atropine is an anti-sialagogue as well as used to antagonize the muscarinic side effects of anticholinesterases. Atropine is detected in the umbilical circulation within 1 to 2 minutes of maternal administration, and an F/M ratio of 0.93 is attained at 5 minutes .

Inclusion Criteria:

• American society of anaesthesiologists (ASA) II
• full term
• singleton
• pregnant women scheduled for elective Cs

Exclusion Criteria:

• patients refusal
• with body mass index (BMI) > 35 Kg/m2
• polyhydramnios
• history of impaired cardiac contractility
• valvular heart disease
• cardiac arrhythmias
• hypertensive pregnancy disorders
• thyrotoxicosis
• cerebrovascular diseases
• foetal abnormalities
• Contraindications to spinal anesthesia as coagulopathy, infection at the site of needle insertion
• uncorrected hypovolemic shock
• increased intracranial pressure from mass effect
• inadequate resources or expertise.