Day 8 of the menstrual cycle
In short: what happens on day 8?
Day 8 of the menstrual cycle is when the fertile window is getting close. The dominant follicle reaches about 12 mm and oestrogen rises quickly. Because sperm can survive for up to 5 days inside the body, a small chance of pregnancy begins from this day in a 28-day cycle.
Day 8 of the menstrual cycle – animated explainer
Day 8: 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
Follicular phase
Chance of pregnancy
Low
Uterine lining
5.5 mm
Follicle
12 mm
FSH
33
LH
20
Oestrogen
41
Basal body temperature
36.31°C
What is happening in your body today?
The uterine lining continues to thicken. Cervical mucus starts to increase.
Hormones
The rise in oestrogen speeds up; FSH stays low.
How you might feel
Energy, confidence and sex drive may increase.
Chance of pregnancy
The chance of pregnancy is low but has begun; sperm from sex today may survive until ovulation.
Tips for today
- If you are planning a pregnancy, make sure you are taking folic acid
- Start noticing changes in your cervical mucus
- Keep eating a balanced diet
When to see a doctor
See your doctor if you have unusual discharge, itching or an unpleasant smell.
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
Can you get pregnant on day 8 of your cycle?
In a 28-day cycle the chance is low but possible; sperm can survive for up to 5 days, so sex on day 8 can still lead to pregnancy if you ovulate on day 13–14.
When does your fertile window start?
The fertile window opens 5 days before ovulation. In a 28-day cycle, that is around day 9.
How long can sperm live inside you?
With fertile cervical mucus, sperm can survive in the female reproductive tract for up to 5 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