Table 1 Trial inclusion and exclusion criteria

Inclusion criteria

 Women with a retained placenta

 Women aged 16 or over

 Women having a vaginal delivery (including women with a previous caesarean section)

 Haemodynamic stability (systolic blood pressure more than 100 mmHg and pulse less than 110 beats per min)

 Over 14 weeks’ gestation

Exclusion criteria

 Unable to give informed consent

 Suspected placenta accreta/increta/percreta

 Multiple pregnancy

 Women undergoing an instrumental vaginal delivery in theatre

 Allergy or hypersensitivity to nitrates or any other constituent of the formulation

 Taken alcohol in the last 24 hours

 Concomitant use of phosphodiesterase inhibitors (such as sildenafil, tadalafil, or vardenafil)

 Contra-indication due to one of the following: severe anaemia, constrictive pericarditis, extreme bradycardia, incipient glaucoma, glucose-6-phosphate dehydrogenase deficiency, cerebral haemorrhage and brain trauma, aortic and/or mitral stenosis and angina caused by hypertrophic obstructive cardiomyopathy, circulatory collapse, cardiogenic shock and toxic pulmonary oedema

 Currently participating in another CTIMP