Which hormones control the menstrual cycle, and how can they be used to prevent or help pregnancy?
The hormones controlling the menstrual cycle (FSH, LH, oestrogen, progesterone), the events of the menstrual cycle, hormonal and barrier methods of contraception, and fertility treatments including IVF.
A focused answer to the OCR Gateway GCSE Biology A topic B3 on hormones in human reproduction, covering FSH, LH, oestrogen and progesterone, the menstrual cycle, contraception and fertility treatments including IVF.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
OCR wants you to describe the roles of the four reproductive hormones, explain the events of the menstrual cycle, describe hormonal and barrier methods of contraception, and outline fertility treatments such as IVF.
The four reproductive hormones
Four hormones control the menstrual cycle. Two come from the pituitary gland and two from the ovaries:
- FSH (follicle stimulating hormone). From the pituitary. Causes an egg to mature in the ovary, and stimulates the ovary to release oestrogen.
- Oestrogen. From the ovary. Causes the uterus lining to thicken, and triggers a surge of LH while inhibiting FSH.
- LH (luteinising hormone). From the pituitary. The LH surge triggers ovulation (the egg is released), around day 14.
- Progesterone. From the ovary (after ovulation). Maintains the uterus lining and inhibits FSH and LH.
The menstrual cycle
The menstrual cycle is about 28 days long, although it varies between people. The key events in order are:
- Days 1 to about 5: the uterus lining breaks down (menstruation, the period), because progesterone has fallen.
- FSH is released, an egg matures, and the ovary releases oestrogen.
- Oestrogen builds up the uterus lining again.
- Around day 14: a surge of LH triggers ovulation (the egg is released).
- After ovulation, the ovary releases progesterone, which maintains the lining ready for a fertilised egg.
- If the egg is not fertilised, progesterone falls, the lining breaks down, and the cycle starts again.
Contraception
Contraception prevents pregnancy. The methods you should know fall into two groups:
- Hormonal methods. The contraceptive pill contains oestrogen and/or progesterone, which inhibit FSH so no egg matures and ovulation does not happen. Other hormonal methods include implants, injections and patches. They are very effective if used correctly, but they do not protect against infection and can have side effects.
- Barrier methods. A condom or diaphragm physically stops the sperm reaching the egg. Condoms also protect against sexually transmitted infections (STIs), which hormonal methods do not.
Other methods include the intrauterine device (IUD) and sterilisation. Different methods are compared on their effectiveness, reversibility and protection against infection.
Fertility treatments
Some people cannot have children naturally, and fertility treatments can help:
- Fertility drugs containing FSH and LH can stimulate the ovaries to mature and release eggs, which helps people whose own FSH levels are too low.
- IVF (in vitro fertilisation). The person is given FSH and LH to mature several eggs, which are collected and fertilised by sperm outside the body (in a laboratory). One or more resulting embryos are then placed back into the uterus.
IVF gives many couples a chance of a baby, but it is emotionally and physically demanding, not always successful, and can lead to multiple births.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20196 marksDescribe the roles of FSH, oestrogen, LH and progesterone in controlling the menstrual cycle.Show worked answer →
A 6-mark extended response. Mark it for the four hormones in a logical order.
FSH (follicle stimulating hormone) is released by the pituitary gland. It causes an egg to mature in the ovary and stimulates the ovary to release oestrogen.
Oestrogen is released by the ovary. It causes the lining of the uterus to thicken and build up, and it stimulates a surge of LH (while inhibiting further FSH).
LH (luteinising hormone) is released by the pituitary gland. The LH surge triggers ovulation (the release of the egg), around day 14.
Progesterone is released by the ovary after ovulation. It maintains the thick uterus lining ready for a fertilised egg, and inhibits FSH and LH. When progesterone falls (if there is no pregnancy), the lining breaks down (menstruation). Markers reward each hormone linked to its correct role.
OCR 20214 marksExplain how the contraceptive pill prevents pregnancy, and describe one disadvantage of using hormonal contraception compared with a barrier method such as a condom.Show worked answer →
A 4-mark question on contraception.
The pill: it contains hormones (oestrogen and/or progesterone) that inhibit the release of FSH, so no egg matures and ovulation does not happen. Without an egg released, there is nothing to fertilise, so pregnancy is prevented. Reward the link from hormones inhibiting FSH to no egg maturing.
Disadvantage compared with a condom: the pill does not protect against sexually transmitted infections, whereas a barrier method (condom) does. Other accepted points: the pill can have side effects; it must be taken regularly to be effective. Markers reward one clear disadvantage, ideally the lack of protection against infection.
Related dot points
- The endocrine system as glands that secrete hormones into the blood, hormones acting on target organs with the correct receptors, the main endocrine glands, and a comparison of nervous and hormonal control.
A focused answer to the OCR Gateway GCSE Biology A topic B3 on the endocrine system, covering glands and hormones, target organs and receptors, the main endocrine glands, and how hormonal control compares with nervous control.
- The control of blood glucose concentration by insulin and glucagon, the roles of the pancreas and liver, negative feedback, and the causes and treatment of type 1 and type 2 diabetes.
A focused answer to the OCR Gateway GCSE Biology A topic B3 on the control of blood glucose, covering insulin and glucagon, the pancreas and liver, negative feedback, and the causes and treatment of type 1 and type 2 diabetes.
- Sexual and asexual reproduction, the formation of gametes by meiosis, how meiosis halves the chromosome number and produces genetically varied cells, and the advantages and disadvantages of each type of reproduction.
A focused answer to the OCR Gateway GCSE Biology A topic B5 on reproduction and meiosis, covering sexual and asexual reproduction, how meiosis halves the chromosome number and produces genetically varied gametes, fertilisation, and the advantages and disadvantages of each type of reproduction.
- The central nervous system, sensory, relay and motor neurones, synapses and neurotransmitters, the reflex arc as a fast automatic response, and reaction time and the factors affecting it.
A focused answer to the OCR Gateway GCSE Biology A topic B3 on the nervous system, covering the central nervous system, the three types of neurone, synapses and neurotransmitters, the reflex arc, and reaction time.
- Auxins as plant hormones controlling growth, phototropism and gravitropism (geotropism), how auxin distribution produces tropic responses, and the commercial uses of plant hormones.
A focused answer to the OCR Gateway GCSE Biology A topic B3 on plant hormones, covering auxins, phototropism and gravitropism, how auxin distribution produces tropic responses, and the commercial uses of plant hormones.