Intramuscular opioids for maternal pain relief in labour: a randomised controlled trial comparing pethidine with diamorphine.
OBJECTIVE
To compare the pain relief and side effects of intramuscular pethidine with intramuscular diamorphine in labour.


METHODS
Double-blind randomised controlled trial.


METHODS
The labour ward in a UK teaching hospital.


METHODS
Sixty-nine nulliparous women and 64 multiparous women in labour who requested narcotic analgesia and remained undelivered one hour after trial entry.


METHODS
Nulliparous women were randomised to receive either 150 mg intramuscular pethidine or 7.5 mg intramuscular diamorphine. Multiparous women were randomised to receive either 100 mg intramuscular pethidine or 5 mg intramuscular diamorphine. All participants received the anti-emetic prochloroperazine at the same time as the trial drugs.


METHODS
Maternal analgesia assessed by a visual analogue score and verbal scales of pain intensity and pain relief, maternal sedation and vomiting, neonatal outcome assessed by Apgar scores and the need for resuscitation.


RESULTS
More women allocated to receiving pethidine than to diamorphine reported slight or no pain relief at 60 minutes after administration of these drugs (P = 0.03). This trend was repeated in most of the other measures for maternal analgesia. There was no difference in maternal sedation, but the incidence of vomiting within 60 minutes was lower for women who received diamorphine (P = 0.02). Pethidine was associated with lower Apgar scores at 1 minute (P < 0.05).


CONCLUSIONS
Intramuscular diamorphine in labour appears to have some benefits, compared with intramuscular pethidine, but the trial was small and further research, particularly into alternative opioids and long term effects on the infants is still needed.
Fairlie
F M
FM
University Department of Obstetrics and Gynaecology, Glasgow Royal Maternity Hospital, UK.
Marshall
L
L
Walker
J J
JJ
Elbourne
D
D
D000701:Analgesics, Opioid / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D003932:Heroin / Q000008:administration & dosage*; D006801:Humans; D007273:Injections, Intramuscular; D008614:Meperidine / Q000008:administration & dosage*; D007744:Obstetric Labor Complications / Q000517:prevention & control*; D010146:Pain / Q000517:prevention & control*; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome
D000701:Analgesics, Opioid; D003932:Heroin; D008614:Meperidine