Uterotonics and tocolytics for anesthesiologists

Management of the third stage of labour: (for the Optimal Intrapartum Care series edited by Mercedes Bonet, Femi Oladapo and Metin Gülmezoglu)

The physiology of the third stage of labour is described. Active management reduces the risk of postpartum haemorrhage (PPH), due to the use of a uterotonic agent. Intramuscular Oxytocin 10 IU has the highest efficacy and lowest side effect profile, although ergometrine, carbetocin and misoprostol are also effective. The appropriate uterotonic in different settings such as home birth by unskilled attendants and at caesarean section is discussed. For the latter, there is less consensus on the optimal dose/route of oxytocin, this topic remaining on the research agenda. Delayed cord clamping enables transfusion of blood to the neonate and is recommended rather than early clamping. Controlled cord traction should only be performed by skilled birth attendants and confers minimal advantage in preventing retained placenta. The importance of early recognition of PPH, and preparedness, is emphasised. An approach to medical and surgical management of PPH is presented.

Oxytocin: Potential to mitigate cardiovascular risk

Cardiovascular disease (CVD) remains the leading cause of death worldwide, despite multiple treatment options. In addition to elevated lipid levels, oxidative stress and inflammation are key factors driving atherogenesis and CVD. New strategies are required to mitigate risk and most urgently for statin-intolerant patients. The neuropeptide hormone oxytocin, synthesized in the brain hypothalamus, is worthy of consideration as a CVD ancillary treatment because it moderates factors directly linked to atherosclerotic CVD such as inflammation, weight gain, food intake and insulin resistance. Though initially studied for its contribution to parturition and lactation, oxytocin participates in social attachment and bonding, associative learning, memory and stress responses. Oxytocin has shown promise in animal models of atherosclerosis and in some human studies as well. A number of properties of oxytocin make it a candidate CVD treatment. Oxytocin not only lowers fat mass and cytokine levels, but also improves glucose tolerance, lowers blood pressure and relieves anxiety. Further, it has an important role in communication in the gut-brain axis that makes it a promising treatment for obesity and type 2 diabetes. Oxytocin acts through its receptor which is a class I G-protein-coupled receptor present in cells of the vascular system including the heart and arteries. While oxytocin is not used for heart disease at present, residual CVD risk remains in a substantial portion of patients despite multidrug regimens, leaving open the possibility of using the endogenous nonapeptide as an adjunct therapy. This review discusses the possible role for oxytocin in human CVD prevention and treatment.