Dr Tessa R Flood, Professor Kirsty J Elliott-Sale

What are hormonal contraceptives?

Hormonal contraceptives (HC) contain exogenous [external] synthetic hormones that act via negative feedback on gonadotrophic hormones resulting in the chronic downregulation of the hypothalamic-pituitary-ovarian axis and endogenous [internal] ovarian sex hormones. The long-term reduction of endogenous oestrogen and progesterone [the ovarian sex hormones] removes the cyclic fluctuations in these hormones associated with the phases of the menstrual cycle. By inhibiting the production of the ovarian hormones, HC reduce the chance of pregnancy by thickening cervical mucus, thinning the lining of the endometrium, and inhibiting ovulation. HC are designed to prevent pregnancy but are also used for a variety of other reasons, for example: to alleviate symptoms of dysmenorrhea (painful periods), lighten or prevent bleeding, prevent acne, reduce variation in cycle lengths, and to treat other medical issues. When discussing athletic performance and contraceptive choices, it is important to remember that it is a women’s right to choose to take HC.