Oestriol is a female hormone that is produced during pregnancy and is responsible for maintaining pregnancy. Synonyms for oestriol include estriol, 16-alpha-hydroxyestradiol, and E3. Estriol is the most commonly used synonym for oestriol and is widely used in medical literature and research. 16-alpha-hydroxyestradiol and E3 are also used interchangeably with oestriol and are known for their role in the regulation of reproductive functions in women. Some other synonyms for oestriol include 16-hydroxyestradiol, 17-beta-estradiol, and 17-beta-hydroxy-1,3,5(10)-estratriene-3-ol-16-one. These synonyms are used by medical professionals to describe the various properties and functions of oestriol in the female body.