Oxytocin
It has been shown that oxytocin differentially affects males and females. Females who are administered oxytocin are overall faster in responding to socially relevant stimuli than males who received oxytocin. Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes; however, males do not show increased amygdala activation. This phenomenon can be explained by looking at the role of gonadal hormones, specifically estrogen, which modulate the enhanced threat processing seen in females. Estrogen has been shown to stimulate the release of oxytocin from the hypothalamus and promote receptor binding in the amygdala.
Postpartum bleeding
Oxytocin helps the uterus to contract quickly and the contractions to last for longer. It is the first line treatment for PPH when its cause is the uterus not contracting well. A combination of syntocinon and ergometrine is commonly used as part of active management of the third stage of labour. This is called syntometrine. Syntocinon alone lowers the risk of PPH. Based on limited research available it is unclear whether syntocinon or syntometrine is most effective in preventing PPH but adverse effects are worse with syntometrine making syntocinon a more attractive option. Ergometrine also has to be kept cool and in a dark place so that it is safe to use. It does reduce the risk of PPH by improving the tone of the uterus when compared with no treatment however it has to be used with caution due to its effect raising blood pressure and causing worse after pains.