Day 16 of the menstrual cycle
In short: what happens on day 16?
Day 16 of the menstrual cycle is when the fertile window closes in a 28-day cycle. The corpus luteum produces more and more progesterone, and the lining of the uterus starts preparing for a possible pregnancy. Cervical mucus thickens, which makes it harder for sperm to pass through.
Day 16 of the menstrual cycle – animated explainer
Day 16: 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
Luteal phase
Chance of pregnancy
Low
Uterine lining
12 mm
Corpus luteum
20 mm
FSH
32
LH
22
Oestrogen
38
Basal body temperature
36.64°C
What is happening in your body today?
If fertilisation has occurred, the embryo divides as it travels through the tube towards the uterus. The uterine lining is around 12 mm.
Hormones
Progesterone rises quickly; oestrogen is low to moderate.
How you might feel
You may notice increased appetite, mild bloating and a calmer mood.
Chance of pregnancy
The chance of pregnancy is low.
Tips for today
- Eat regular, balanced meals to keep your blood sugar steady
- Moderate exercise feels good
- Eat magnesium-rich foods (nuts, green vegetables)
When to see a doctor
See your doctor if you have unusual bleeding, severe pain 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
Can you get pregnant on day 16 of your cycle?
In a regular 28-day cycle, the chance is low. If ovulation was late, the chance may be higher.
Why does discharge decrease after ovulation?
Progesterone makes cervical mucus thicker and reduces the amount.
How long is the luteal phase?
The luteal phase usually lasts 12–14 days and stays fairly constant regardless of cycle length.
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