Hormonal methods of contraception Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Understanding how hormonal contraceptives work, including oral contraceptives that inhibit FSH production and slow-release progesterone methods such as...

• Explain how oral contraceptives prevent pregnancy by inhibiting FSH production
• Describe how progesterone-based contraceptives work to prevent egg maturation and release
• Compare the effectiveness and duration of different hormonal contraceptive methods
• Evaluate the advantages and disadvantages of hormonal contraception methods

Key ideas to keep in view

Use this lesson to stay inside B3.2 Coordination and control - the endocrine system while connecting the detail back to the wider B3: Organism level systems topic.

• B3: Organism level systems
• B3.2 Coordination and control - the endocrine system
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Hormonal methods of contraception before testing yourself from memory.

• Your body runs on a delicate hormone cycle every month. Hormonal contraceptives hijack this natural system to prevent pregnancy. Instead of fighting biology, they use it - tricking your body into thinking it's already pregnant or that eggs shouldn't be released.
• There are two main approaches: stopping eggs from maturing in the first place, or preventing their release even if they do mature. Both methods target the pituitary gland - the master controller of your reproductive hormones.
• Methods of preventing pregnancy that use synthetic hormones to disrupt the normal menstrual cycle by inhibiting egg maturation, ovulation, or both.
• Trap: Many students think hormonal contraceptives kill eggs or sperm. Actually, they prevent eggs from developing or being released in the first place - no egg means no fertilisation can occur.
• Combined oral contraceptive pills contain synthetic oestrogen and progesterone, while some contraceptive pills contain progesterone only. These hormones send a false signal to your pituitary gland: 'Don't release FSH, we don't need any eggs to mature this month.'
• The suppression of follicle stimulating hormone production by the pituitary gland, which prevents eggs from maturing in the ovaries.
• Here's the clever part: when synthetic hormones are detected in your bloodstream, your pituitary gland reduces FSH production through negative feedback. No FSH means follicles in your ovaries don't develop. No mature follicles means no eggs ready for fertilisation.
• This is why the pill must be taken daily - you need constant hormone levels to maintain FSH suppression. Miss too many pills and FSH production resumes, allowing eggs to start maturing again.
• Progesterone-only contraceptives work differently from the pill. Instead of stopping egg maturation completely, they focus on preventing ovulation - the release of mature eggs from the ovaries.
• Synthetic progesterone hormones delivered via injection, implant, or skin patch that inhibit egg maturation and release for months or years.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.