DSE Biology | Human Reproduction and Contraception: the Menstrual Cycle, Four Hormones and Birth Control (teacher prep) | one 28-day timeline that answers every question

2026-11-05

Tutor lesson-prep guides · Secondary Biology

Students memorise four hormone names and lose the thread at the first question about the corpus luteum. This lesson puts all four hormones on one timeline.

Objectives — Students can: (1) mark menstruation, ovulation on day 14 and the luteal phase from day 15 to day 28 on a 28-day timeline; (2) state where FSH, LH, oestrogen and progesterone peak and why; (3) use a 24-hour egg and 5-day sperm to explain why the fertile window is day 9 to day 14.

01 Prerequisites (3-minute check)

If any of these fails, fix it before the lesson starts.

Skill	Quick check	Pass mark
Cell division	What does meiosis produce?	Four haploid cells
Endocrine basics	How do hormones differ from nerve impulses?	Blood-borne, slower and longer lasting
Reproductive organs	Where does fertilisation happen?	Ampulla of the fallopian tube

02 Lesson flow (45 minutes)

Time	Stage	Tutor does	Student does
0-5 min	Start with one date	Ask what happens on day 14 and why 14, no hints	Silence or a wrong answer
5-15 min	Draw the 28-day timeline	Three layers: ovary, uterine lining, four hormones	A timeline with four curves
15-27 min	The hormone relay	FSH recruits, oestrogen surges, LH triggers, progesterone holds	Each step stated as cause and effect
27-38 min	Fertile window	Egg 24 hours, sperm 5 days	Day 9 to 14, 6 days
38-45 min	Contraception and exit check	Hormonal, barrier, surgical, one example each	Three out of three

03 Teaching script (read it out)

Scene 1: Draw the timeline before naming any hormone

Draw a 28-day line on the board with three layers: the ovary (follicle growth, an ovulation arrow on day 14, the corpus luteum from day 15 to day 28); the uterine lining (shed on days 1 to 5, then thickening, thickest after ovulation); and only then the four hormone curves. Students want to recite names first, so hold their hand still: events come before hormones.
Fix three points on the line: ovulation on day 14, the LH surge on day 13, progesterone highest around day 21. Every later question is answered by pointing back at a day on this line.

Ask the student: why is ovulation on day 14 rather than day 1?

Scene 2: Four hormones are a relay, not four names

FSH from the pituitary grows the follicle; the growing follicle secretes oestrogen, which suppresses FSH and then surges near mid-cycle (positive feedback) to trigger the LH peak; the LH peak on day 13 causes ovulation about 24 to 36 hours later; the ruptured follicle becomes the corpus luteum and secretes progesterone, which thickens the lining further and suppresses FSH and LH.
After the relay, ask it backwards: what happens when progesterone falls? The answer is menstruation, and only then is the cycle understood. Without fertilisation the corpus luteum regresses about 14 days after ovulation, progesterone drops and the lining is shed.

Ask the student: progesterone protects a pregnancy, so why does it fall?

Scene 3: The fertile window comes from two survival times

An egg can be fertilised for about 24 hours and sperm survive about 5 days in the female tract, so viable sperm must arrive between day 9 and day 14, a window of 6 days. The same arithmetic explains why rhythm methods fail (ovulation shifts) and why emergency contraception works better the earlier it is taken.
Then make the student move the numbers: with a 35-day cycle ovulation is around day 21 and the window shifts with it. Same logic, different numbers, and that transfer is what the exam tests.

Ask the student: with a 35-day cycle, which days form the fertile window?

04 Question types and worked steps

Type	Example	Steps	Answer
Timeline labelling	Mark ovulation and the luteal phase	Fix day 14, count back 14 for the follicular phase, forward 14 for the luteal	The luteal phase is fixed at 14 days
Hormone function	Explain why a hormone rises or falls	Name the source, the target, then one cause-and-effect sentence	Four hormones, four sources
Cycle calculation	Find the fertile window or the next period	Ovulation = cycle length minus 14, window = five days before to ovulation day	28-day cycle gives days 9 to 14
Contraception comparison	Compare two methods	Classify first, then state which step is blocked	Hormonal methods block the LH surge

Sanity check (teach this): Three numbers must agree: a 28-day cycle, ovulation on day 14, a 14-day luteal phase, and 14 plus 14 is 28. The window of 6 days is the 5-day sperm life plus the day of ovulation, never more. An answer of days 1 to 14 means the sperm lifespan was treated as 14 days, so send the student back to recalculate.

05 Independent practice (3 questions)

Question	Answer	What to watch
In a 28-day cycle, which days form the fertile window?	Day 9 to 14, 6 days	Whether the 5-day sperm life was included
Which structure secretes progesterone after ovulation?	The corpus luteum	Answering placenta means pregnancy is being confused with the cycle
In a 35-day cycle, ovulation is around which day?	Day 21	Whether the rule subtract 14 was used instead of memorising 14

06 Common mistakes and what to say

Mistake	Student writes	Say this
Swapping oestrogen and progesterone	Writing that progesterone grows the follicle	Read the timeline: oestrogen in the follicular phase, progesterone after ovulation.
Thinking a rise in progesterone causes menstruation	Writing that progesterone rises and then bleeding starts	It is the fall that causes it; the drop is the cause, not the result.
Quoting ovulation day only	Answering that only day 14 can conceive	Sperm wait five days, so the window opens on day 9.
Calling the pill a spermicide	Mixing hormonal contraception with spermicide	The pill suppresses the LH surge so no egg is released.

07 Homework (paper, section and question numbers)

DSE Biology reproduction practice paper — Questions 1 to 3: redraw the 28-day timeline with all four hormone peaks before answering.
Same paper, hormone comparison — Question 5: tabulate the source, target and effect of FSH and LH in eight words or fewer per cell.

08 Exit check (last 5 minutes)

Question	Answer	Decision
Which day is ovulation	Day 14	Answering day 1 means the timeline needs redrawing
Why does progesterone fall	No fertilisation, so the corpus luteum regresses	Answering because menstruation starts reverses cause and effect
How long is the fertile window	6 days, day 9 to day 14	Answering one day ignores the 5-day sperm life

09 Tutor FAQ

Must all four hormones be memorised?

Learn the source, the target and one effect each, but derive the order from the timeline rather than memorising four curve shapes.

Why is the rhythm method unreliable?

Ovulation can shift by days with stress or illness, and sperm survive five days, so one shifted day breaks the estimate.

Is the cycle always 28 days?

No, 21 to 35 days is common; the luteal phase is the fixed part at about 14 days and the follicular phase varies.

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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.