After obtaining IEC approval and informed consent, all the eligible patients will be recruited for the study. It will be an open label, a non-blinded, randomised controlled study. The study participants will be randomly allocated into the two groups (Group A, Group B). Randomization is done by computer-generated software (www.randomizer.org). The randomization sequence will be generated using random number generator. The random allocation sequence will be placed in sealed numbered opaque envelopes for strict number order assignment to participants. Participants randomized to Group A will be permitted light meal until 6 hours and to clear fluids and water until 2 hours before surgery. Participants randomized to Group B will be permitted light meal until 8 hours and to clear fluids and water until 6 hours before surgery.

Clear fluids can be (water, oral rehydration solution (dextrose approx. 75 gm in 200 ml), sucrose solution (approx. 35 grams, four teaspoons of the powder Glucon D, to 200 ml of water), black tea/coffee or coconut water) will be given freely until 2 hours before scheduled caesarean surgery to Group A. The total amount of preoperative clear fluids intake will be recorded for 6 hours before surgery in Group A. The amount of fluid intake taken will be as per the patient’s thirst, choice and tolerance.

The operating theater staff would call for patients to be sent to the obstetric operating theater from the antenatal ward 15-30 minutes before expected entry into the operating theater for commencement of spinal anesthesia, bladder catheterization, and immediate follow-on cesarean section. Patients will be kept at reception bay of the recovery area if the operating theater is not immediately available.

Demographic data and clinical characteristics, such as age, weight, body mass index (BMI), gestational age, parity, previous C-section, fasting time, and time and type of food taken as last diet, in both the groups will be recorded on arrival to the operating room. Abdominal ultrasonography will be performed in the sagittal or para-sagittal plain in the right lateral decubitus position. Sonographic landmarks such as the liver, aorta, vena cava, and pancreas, as well as the classical appearance of the gastric antrum, will be used in sonography to identify the antrum in the scanning area. The probe will be tilted as needed to ensure a proper transverse view of the antrum, avoiding oblique images that may have resulted in an overestimation of the cross-sectional area of the antrum. Three consecutive still images will be obtained, labelled, and stored. The two antral diameters will be measured from serosa to serosa (7). All images will be obtained with the antrum at rest, not during peristaltic contractions. The cross-sectional area (CSA) of the antrum will be calculated according to the formula described by Bolondi et al. (8) using two maximum perpendicular diameters representing the surface area of an ellipse, as follows: CSA = AP × CC × π/4 (AP, anteroposterior diameter; CC, craniocaudal diameter). The mean of the three measurements will be used as the CSA value. Measurement of the antral area will be performed by an anesthesiologist or obstetrician skilled in image acquisition and identification (experience of using ultrasound for > 2 years) of the gastric antrum by using a curvilinear array, low frequency (2 to 5 MHz) transducer of Sonosite Edge II Ultrasound Machine.

Before surgery, an intravenous line will be established on the non-dominant hand using 18 G size intravenous cannula. The multi-channel monitor will be attached, and baseline parameters of pulse rate, blood pressure (systolic, diastolic, and mean), electrocardiography (lead II, V) and SpO2 will be recorded. Under aseptic precautions, with the patient in a sitting/lateral position, the subarachnoid blocks will be performed at L3-L4 or L4-L5 intervertebral spaces and will receive 10 mg of intrathecal Hyperbaric Levobupivacaine (0.5%) or bupivacaine (0.5%).

Vasopressors will be administered when the systolic blood pressure falls below 90 mmHg or decreased by > 20% of the baseline value. As a vasopressor, phenylephrine (50 mcg) will be administered for hypotension with HR ≥ 60 beats/min or ephedrine (5 mg) for hypotension with HR < 60 beats/min. We will count the administration of 100 mcg of phenylephrine or 5 mg ephedrine as one dose. After birth, oxytocin (05-15 units) diluted in ringer’s lactate will be administered to stimulate uterine contraction. During surgery and every 8 hrs after surgery for 24 hrs, all patients will be given paracetamol 1000 mg IV  8th hourly. After surgery, all patients will be shifted to PACU (post anaesthetic care unit). Patients will be shifted from PACU after completing 9 points in the modified Aldrete post-anaesthetic recovery scale. If a patient requests additional analgesia (VAS ≥3), they will be treated with slow IV infusion of inj. Tramadol hydrochloride (50 mg) and or IV ketorolac 30 mg. For nausea and vomiting episodes, ondansetron (4 mg) will be prescribed.

The following outcome measures will be evaluated

The cross-sectional area of the gastric antrum will be measured upon arrival at the operation theatre. Heart rate, BP, SpO2, the need for supplemental analgesics, and the occurrence of certain side effects (nausea, vomiting, hypotension episodes, and treatment required) will be recorded intraoperatively and at four-hour intervals throughout the first 24 hours postoperatively.

Nausea and pruritus will be graded using a 4-point scale, where 0 = none, 1 = mild (requiring no treatment), 2 = moderate (responsive to treatment), and 3 = severe (unresponsive to ondansetron 8mg). Postoperative vomiting will be assessed using a different 4-point scale as follows: 0 = none, 1 = one to two episodes, 2 = 3 to 4 episodes, and 3 = more than 4 episodes. Before surgery, patients will be instructed about the use of the visual analogue scale (VAS; 0-10 cm), with 0 and 10 labelled as "no pain" and "worst pain imaginable," respectively. The VAS scores, nausea, vomiting and itching scores will be recorded at 3, 6, 12 and 24 hours after surgery for 24 hours. Time to pass flatus, time to return of bowel sounds, length of hospital stay, and maternal satisfaction (Likert Scales for thirst, hunger) will also be recorded.

Maternal and foetal side effects: Incidences of nausea or vomiting, hypotension, and medication need will be recorded perioperatively and up to 24 hours after surgery. Apgar scores for the neonates will be recorded at one and five minutes after delivery.