Sublingual glyceryl trinitrate for uterine relaxation at Caeserean section--a prospective trial

We report a prospective study on the use of sublingual glyceryl trinitrate at Caesarean section to induce uterine relaxation; 23 women were entered into the study with both emergency and elective cases considered. A metered dose spray was used to deliver a dose of 400 or 800 microgrammes of glyceryl trinitrate to the women. There were no major side-effects of hypotension or postpartum haemorrhage. The mean maximal systolic blood pressure drop in the patients following drug administration was 18% of the systolic pressure prior to drug administration. Subjective assessment of uterine tone showed the uterus to contract well postdelivery in response to standard oxytocic regimens. Minimal maternal side-effects were reported. We conclude that glyceryl trinitrate is a safe form of uterine relaxation at Caesarean section which may be used in emergency situations and may also be given prophylactically in cases such as breech presentation and in delivery of the preterm infant where fetal trauma is possible. The use of a metered-dose sublingual spray is ideally suited to obstetric practice, being both easy to use and also rapidly administered.