Effect of Each Trimester Weight Gain in Pregnancy on Maternal Hemodynamics during Elective Cesarean Section after Subarachnoid Blockade

Abstract

Background: Pregnancy is associated with significant physiological and haemodynamic changes, and spinal anaesthesia may produce a greater fall in blood pressure because of sympathetic blockade. Maternal weight gain during pregnancy may influence haemodynamic responses to subarachnoid blockade. This study evaluated the effect of weight gain during each trimester on maternal heart rate changes and spinal-induced hypotension during elective caesarean section.

Methods: This observational cross-sectional study was conducted in a Tertiary Care Centre, South India for a period of 22 months. Ninety-three healthy singleton term parturients aged 18–35 years with normal pre-pregnancy BMI and ASA II status were included and divided into three groups according to total pregnancy weight gain: Group A (8–10 kg), Group B (11–13 kg), and Group C (>13 kg), with 31 participants in each group. Standardized spinal anaesthesia with 2 mL of 0.5% hyperbaric bupivacaine was administered. Heart rate and blood pressure were recorded immediately after spinal anaesthesia and every 5 minutes for 45 minutes.

Results: Mean total weight gain was 9 kg, 11.74 kg and 14.44 kg in Groups A, B and C, respectively. Baseline heart rate did not differ significantly among groups. Baseline systolic blood pressure was significantly lower in Group A. The frequency of hypotension was significantly higher in Group A than Group C (p=0.044), with a greater mephentermine requirement in Group A (7.55 mg vs 4.84 mg and 3.10 mg; p=0.015). However, weight gain in individual trimesters was not significantly associated with hypotension or heart-rate changes. Newborn birth weight was significantly lower in Group A (2.81 kg) than Groups B (2.99 kg) and C (3.26 kg). APGAR scores were comparable.

Conclusion: Inadequate maternal weight gain, particularly below 11 kg, was associated with lower baseline systolic blood pressure, increased incidence of hypotension following subarachnoid blockade, greater vasopressor requirement and lower neonatal birth weight. However, individual trimester weight gain was not associated with haemodynamic changes.