Oestrogen

 Oestrogen is present in all vertebrates and some insects. It is a steroid hormone, produced in the ovaries, and it is most commonly recognised as a female sex hormone. It is part of the estrous cycle which helps to control the menstrual cycle. It can be used as a birth control method and is in the combined pill. It is also present during pregnancy when it is produced by the placenta.  

Non-steroidal Oestrogens can also be synthesised. These fall into three categories: Phytoestrogens, Xenoestrogens and Mycoestrogens. 

Oestrogen can also effects some cancers and womens mental health.