Day 3 of the menstrual cycle
In short: what happens on day 3?
Day 3 of the menstrual cycle is usually when period bleeding starts to ease. FSH approaches its highest levels and speeds up the growth of follicles in the ovaries. This is why ovarian reserve tests such as FSH, LH, oestrogen and AMH are usually done on day 2–3 of the cycle.
Day 3 of the menstrual cycle – animated explainer
Day 3: cycle dial, uterus and ovaries, hormone levels (illustrative animation).
What the animation shows
- FSH
- Follicle-stimulating hormone: starts the growth of follicles in the ovary
- LH
- Luteinising hormone: its sudden surge triggers ovulation
- E2
- Oestrogen (oestradiol): thickens the lining of the uterus
- P4
- Progesterone: prepares the uterus for a possible pregnancy
- BBT
- Thermometer and dots below: basal body temperature
- RING
- Coloured ring: the 28-day cycle and its phases; the green arc marks the fertile days
- MM
- The measurement in the uterus shows lining thickness; in the ovary it shows follicle or corpus luteum size
Phase
Menstrual phase (period)
Chance of pregnancy
Very low
Uterine lining
3 mm
Follicle
6 mm
FSH
55
LH
18
Oestrogen
17
Basal body temperature
36.33°C
What is happening in your body today?
The uterine lining continues to thin. As the follicles grow, they begin to produce small amounts of oestrogen.
Hormones
FSH nears its early follicular peak. Oestrogen slowly begins to rise.
How you might feel
Cramps usually ease. Tiredness may continue, but energy gradually returns.
Chance of pregnancy
The chance of pregnancy is very low.
Tips for today
- If you are having hormone tests, plan them for the day your doctor recommends
- Foods rich in vitamin C improve iron absorption
- Keep a regular sleep routine
When to see a doctor
See your doctor if bleeding gets heavier instead of lighter, or if you have foul-smelling discharge or a fever.
Menstrual cycle day by day: table
| Day | What happens | Fertile window |
|---|---|---|
| Day 1 | First Day of Your Period | — |
| Day 2 | Heaviest Bleeding Day | — |
| Day 3 | FSH Rises, Follicles Grow | — |
| Day 4 | Bleeding Eases, Oestrogen Rises | — |
| Day 5 | Last Day of Your Period | — |
| Day 6 | Follicular Phase Begins | — |
| Day 7 | Dominant Follicle Is Selected | — |
| Day 8 | Oestrogen Rises, Fertile Window Nears | Low |
| Day 9 | Fertile Window Begins | Moderate |
| Day 10 | Fertile Window, Higher Pregnancy Odds | Moderate |
| Day 11 | 3 Days Before Ovulation | High |
| Day 12 | Oestrogen Nears Its Peak | High |
| Day 13 | LH Surge: Ovulation Is Near | Highest |
| Day 14 | Ovulation Day | Highest |
| Day 15 | Luteal Phase Begins | Moderate |
| Day 16 | Progesterone Rises | Low |
| Day 17 | Luteal Phase and Increased Appetite | — |
| Day 18 | Breast Tenderness May Start | — |
| Day 19 | Implantation Window Opens | — |
| Day 20 | Implantation Bleeding Possible | — |
| Day 21 | Progesterone Peak (Day 21 Test) | — |
| Day 22 | Mid-Luteal Phase | — |
| Day 23 | PMS Symptoms May Start | — |
| Day 24 | Hormones Start to Fall | — |
| Day 25 | Late Luteal Phase and PMS | — |
| Day 26 | Progesterone Drop and Cramps | — |
| Day 27 | 1 Day Before Your Period | — |
| Day 28 | Last Day of Your Cycle | — |
Frequently asked questions
Why are hormone tests done on day 3 of your cycle?
On day 2–3 oestrogen and progesterone are low, so FSH and LH levels reflect ovarian reserve more accurately. AMH, on the other hand, can be measured on any day of the cycle.
What is a normal FSH level on day 3?
A level between 3 and 10 mIU/mL is generally considered normal. Reference ranges vary between laboratories, so discuss your result with your doctor.
Does your period get lighter on day 3?
For most people, yes. Bleeding usually eases after day 3 and stops within 3–7 days.
Gynaecology check-ups and follow-up at SoftCare Clinic
Book an appointment with our specialist doctors for irregular periods, painful periods or pregnancy planning.
The information on this page is general guidance based on a typical 28-day cycle and does not replace a medical examination. It should not be used as a method of contraception.
Medical content editor: Op. Dr. Şükrü Sanus