What hormones are in contraception and what effect do they have on your body?

Hormonal contraceptives are made up of the alternate and synthetic forms of the female sex hormones oestrogen and progesterone. The synthetic form of progesterone is referred to as progestin. 

So, to give you a better understanding of how the hormones in contraceptives work, let’s backtrack a little bit and talk about the normal functioning of the female sex hormones.


Hormones in general, are what you can call “chemical messengers” that tell the body what to do, when, and how. Oestrogen and progesterone are responsible for the reproductive function and the menstrual cycle of a woman. They are both produced in and released from a woman’s ovaries.

Oestrogen causes the ovaries to release an egg in a process known as ovulation. Progesterone prepares the body for pregnancy by causing the uterus lining to thicken.

If a woman ovulates and the egg is not fertilised or implanted, oestrogen and progesterone levels fall, and this causes the uterus lining to shed, and that’s how you get your period.

When a woman falls pregnant, her body releases high levels of both oestrogen and progesterone. These high levels prevent further ovulation during pregnancy.

Now that we have understood how these hormones operate in relation to periods and pregnancy, we can explore how they work as contraceptives.

Hormonal contraceptives contain either a combination of oestrogen and progestin or just progestin alone. These types of contraceptives alter the natural production and patterns of oestrogen and progesterone. This means that they also alter the natural pattern of periods and ovulation. 

By changing the normal levels of oestrogen and progesterone, hormonal contraceptives work by:

1) Preventing ovulation

2)Thickening cervical mucus (Which blocks sperm from entering the uterus)

3) Sometimes thinning the uterus lining to prevent implantation

Positive effects:

Hormonal contraceptives can:

1)Minimise acne

2)Minimise ovarian cysts

3)Reduce menstrual pains

4)Cause periods to become lighter and better regulated

Negative effects:

The changes in hormonal levels caused by hormonal contraceptives can:

1)Cause mood swings and depression

2)Possibly cause some weight gain (in the case of the depo provera)

3)Cause breast tenderness

4)Lower your libido

Always keep in mind that what one woman may experience may not be what you experience. Everybody’s body is different.

If you are looking for a contraceptive but are not sure what will work for you, visit our website maps page and locate a gynaecologist near you to help you make your decision. You can also check out our blog article on types of modern contraceptives to help you understand what’s out there.