Dexamethasone for prevention of spinal hypotension during caesarean delivery: a randomised controlled trial

The Takeaway

8 mg of intravenous dexamethasone significantly reduced the incidence of spinal hypotension during caesarean delivery.

Study Design

• Randomised, double-blind, placebo-controlled trial
• Inclusion criteria: age >18 years; ASA status 2; singleton pregnancy, gestational age >37 weeks
• Exclusion criteria: history of gestational diabetes or chronic diabetes, hypertensive disorders of pregnancy, cardiovascular insufficiency, body mass index >40 kg/m², allergy to study drugs, participants with underlying medical conditions using long-term steroids, any contraindications to spinal anaesthesia
• Primary Outcome: prevention of spinal hypotension in women undergoing elective caesarean delivery
• Secondary outcomes: phenylephrine use, incidences of postdelivery hypotension, maternal bradycardia, nausea and/or vomiting, shivering, and maternal glycaemia and neonatal outcomes (Apgar scores and umbilical arterial pH).

Abstract

Background: Surgical tissue trauma induced by cesarean delivery serves as a pivotal stimulus for initiating the activation of nociceptors, leading to severe postoperative pain. Dexamethasone seems to mitigate pain-elicited inflammatory response and potentially serve as an analgesic adjunct in the post-cesarean period. This systematic review and meta-analysis aimed to assess the administration of intravenous dexamethasone for post-cesarean pain management.

Methods: An electronic database search involving PubMed, Scopus, CENTRAL, and the Public Library of Science was conducted to identify all randomized controlled trials (RCTs) pertinent to the analgesic efficacy of intravenous dexamethasone compared with placebo for cesarean delivery. The risk of bias and certainty of evidence in eligible trials were assessed using the ROB2 tool and the GRADE approach, respectively.

Results: Seventeen RCTs were included in the qualitative analysis, and 15 in the quantitative analysis. Intravenous dexamethasone was associated with prolonged time to first request for rescue analgesia (mean difference [MD] 3.33 hours, 95% CI 1.67 to 4.99; I² = 92.7%), lower opioid analgesic consumption (MD, -3.23 mg; 95% CI, -4.04 to -2.41; I² = 67.5%) within 24 hours and improved pain scores up to 24 hours postoperatively compared with placebo, however prediction intervals failed to confirm these favorable effects. The risk of postoperative nausea and vomiting was reduced with intravenous dexamethasone, but not that of pruritus.

Conclusions: Intravenous perioperative dexamethasone seems to be a promising adjunct to established analgesic modalities in cesarean delivery, with prolonged time to first request for rescue analgesia, reduced analgesic consumption, and reduced pain scores at rest up to 24 hours postoperatively. However, the substantial heterogeneity and low certainty of available evidence preclude any definite conclusions from being drawn.

Physiology Review

When we perform spinal anesthesia, we're injecting local anesthetic into the subarachnoid space, where it mixes with cerebrospinal fluid and blocks nerve transmission. The key to understanding the resulting hypotension lies in what nerve fibers are affected.

Spinal anesthesia doesn't just block sensory and motor nerves—it also blocks autonomic sympathetic fibers, particularly the preganglionic sympathetic fibers that exit the spinal cord from T1 to L2.

Here's what happens next:

1. Sympathetic Blockade: The most immediate and significant effect is vasodilation due to the blockade of sympathetic tone to the arterioles and venules, especially in the lower extremities and splanchnic circulation. The arterioles lose their vasoconstrictive tone, which causes a drop in systemic vascular resistance (SVR) and venous pooling, decreasing venous return to the heart (preload).
2. Decreased Cardiac Output: The decreased preload means the heart has less volume to pump, so cardiac output drops. This effect is magnified if the sympathetic block extends up to or above T4, where the cardioaccelerator fibers are located. If these are blocked, you can also lose sympathetic input to the heart, leading to bradycardia, which further lowers cardiac output.
3. Resulting Hypotension: The hypotension after spinal anesthesia is primarily due to vasodilation and decreased venous return, leading to reduced cardiac output, and in some cases, compounded by bradycardia from cardioaccelerator fiber blockade.

You’ll often see this drop in blood pressure within minutes after the block is initiated, especially in volume-depleted patients or those with high levels of spinal blockade.

Excerpts

spinal anaesthesia is associated with maternal hypotension during CD, the incidence of which has been reported to be 50–60% in non-labouring patients

Spinal block leads to vasodilation, hypotension, and bradycardia because of sympathetic blockade, the Bezold-Jarisch reflex and 5-HT3 receptor stimulation, present in vagal nerve endings

For prevention and treatment of spinal hypotension during CD, various strategies, including intravenous fluid therapy, vasopressors, ondansetron, left uterine displacement, and leg compression, have all been used with varying degrees of success

Dexamethasone, a synthetic glucocorticoid, increases peripheral vascular resistance by decreasing vasodilatory nitric oxide, increasing sympathetic activity and elevating plasma epinephrine and dopamine. Dexamethasone also increases the sensitivity of vascular endothelial receptors to various vasoconstrictors by reducing 5-HT3 levels, reducing Bezold-Jarisch reflex-mediated hypotension

The incidence of spinal hypotension (decrease in SBP >20% of baseline) from spinal anaesthetic dose to delivery was significantly lower in group D (18.8%) compared to group C (38.8%)

Dexamethasone was found to be effective in preventing a decrease in SBP, MAP and DBP and an increase in heart rate post-spinal anaesthesia. Requirement of vasopressor (phenylephrine) for the management of hypotension and the incidence of nausea, vomiting and shivering was also less with dexamethasone.

In another randomised trial comparing the efficacy of ephedrine versus ondansetron versus dexamethasone in the prevention of spinal hypotension in caesarean delivery, ondansetron was more effective compared to dexamethasone followed by ephedrine

Article Link

Citation

Ioannopoulos D, Tsani Z, Chatsiou E, Arnaoutoglou E, Tsaousi G. Efficacy and safety of intravenous administration of dexamethasone on post-cesarean delivery pain: a systematic review and meta-analysis of current literature. Int J Obstet Anesth. 2025 May 12;63:104682. doi: 10.1016/j.ijoa.2025.104682. Epub ahead of print. PMID: 40398157.