The MHRA has noted that terbutaline is ineffective in the provision of acute tocolysis in premature labour and has been associated with a risk of serious and potentially fatal cardiovascular events such as myocardial infarction and pulmonary oedema in the mother and cardiomegaly in the fetus, which increased with duration of use. Therefore, the risks associated with use of the oral formulations were considered to outweigh the benefits.